My Timing

I also have the Mallory unilite and until this weekend I was running about 30 initial. It seemed to drag on the starter motor just a bit so I backed it down to twenty. She starts fine, runs fine and doesn't diesel when I shut it off. I am happy.

27 degrees would be questionable on a mildly tuned motor, if the 27 number were reliable. It isn't. neither were the markings on your previous motor. Unless blue printed, the markings on the balancer are never accurate.

your friend on the DTBB

So what's the point? Do I just adjust it to where the engine is performing at what seems best? My plan is to do the final adjustments while driving with the help of a friend, of course.

Set the initial timing at the point where the motor idles the fastest, the intake manifold vacuum is the highest, with the vacuum advance connected normally, engine up to operating temp.

Your centrifugal advance will not be appropriate to work with this new static setting, but the appropriate amount of total advance can only be determind on a dyno. Its very normal after a dyno run to need to have the distributor recurved. In the mean time, so long as the motor is not pinging, it doesn't hurt a thing, it will merely be down on power above 3000 rpm. But what this setting will do for drivability and throttle response is wonderful. It also helps the carburetor to work properly. In your case, it sounds as if you're close already.

your friend on the DTBB

Yep, I agree with George. When I was running about 30 she would run like a stripped ass ape above 3 grand. But I like being able to start my car easily so I turned it down.

I'm just curious DT. If you don't use a timing light how do you know it was 30 degrees? Do you have another part of your body calibrated to read the timing?
I hear that some people can tell depending on the voltage that goes through thier body. If it just throws you against the wall it isn't as advanced as if it knocked you unconcious.

I adjusted my timing this past weekend too. Per your advice, George, I advanced the timing until I got the motor RPM to increase to the max. I checked it then with my timing light, about 32 degrees. I backed down to 20 degrees but have not had a chance to drive it. I have a FluidDamper crankshaft damper with very accurate degree marks but like you say the pointer could be off. Could it be off as much as 10 to 15 degrees? The pointer is not bent or anything. Any good way to check it?

Well yeah my calibrated ass can tell. Drag racers run 30 plus initial and as much as 60 all in. It felt and sounded like that. SO yeah, the ear comes into play too. And the old achoholic eyeball is ably to judge ten degrees of rotation. When I was a young pup I could read as venier caliper down to .010. Now I am lucky to be able to see .020".

George,
I had Russ mark my damper at 34 and when I got the motor in thats where I set it, and it starts easy and runs awesome. my ? is because of the cam and the Webers is that why my timing is so different from everyones.
Thanks
Webers Rock
Dennis

quote:

Originally posted by BD:
...Could it be off as much as 10 to 15 degrees? The pointer is not bent or anything. Any good way to check it?...

One of the things we are taught in science, is the difference between precision and accuracy. One of those racy dampeners, with the distinctly stamped white numbers on a black background, is very precise. But that does not mean that the zero mark is accurately set at TDC of cylinder #1. You already mentioned one variable, the pointer. Two other variables are the keyways broached into the crankshaft snout and into the ID of the dampener. Each degree on the crankshaft snout is only 0.008” apart. If the errors of the pointer and both keyways happen to be additive in your motor, it would be very easy for them to be off by 15 degrees, or more.

When I rebuild a motor, I find TDC of cylinder #1 and accurately scribe a mark on the dampener in alignment with the pointer. I’ve never found a dampener accurately marked. So the weekend mechanic, who painstakingly sets the timing of his motor with his timing light to factory specs, is communing with his car, his Zen is wonderful, but his timing can be way off.

I recommend you connect your vacuum advance mechanism to “ported” vacuum, vacuum advance is only needed while cruising, not at idle. With the car warmed up, twist the distributor to just achieve the fastest idle or highest intake manifold vacuum. Regardless of what number you assign to this setting, it IS the proper setting for your motor. Unless you have a radical camshaft in your motor, the initial timing “should” fall into the 20 to 24 degree range, regardless of what your timing marks may read. Total timing can only be determined on a dyno, afterwards the distributor should be pulled, and recurved to take the motor from initial timing to total timing, and no further. If the dampener read 20 degrees at idle, and reads 30 degrees on the dyno when optimized for total advance, then you know your distributor should be calibrated for 10 degrees of centrifugal advance. When the ignition is dialed in like this, the motor runs much stronger, and the carb is easier to tune. Keep in mind; carb tuning and ignition timing are fairly interactive.

As cam timing gets more and more racy, a motor requires more and more initial timing at idle, until eventually the difference between initial timing and total timing becomes little to none. As initial timing increases, the motor can become harder to crank, especially a high compression motor. Ford manufactured a Duraspark module that featured “cranking retard”, MSD also sells modules with this feature. This feature electronically retards the ignition timing while the motor is being cranked, specifically to make it easier for the starter to spin the crankshaft.

There is a way to determine TDC on an assembled motor. Gut a spark plug and thread a piece of threaded rod into it, sticking out perhaps an inch or so. (a similar “tool” is available retail that accomplishes the same thing). Screw this contraption into the spark plug hole of cylinder #1. Turn your motor’s crankshaft slowly until the piston just kisses the rod sticking into the cylinder. Mark this spot on the dampener in alignment with the pointer. Next slowly turn the crankshaft in the opposite direction until the piston just kisses the rod from that direction. Again mark this spot on the dampener in alignment with the pointer. TDC will be ½ way between your two marks.

quote:

Originally posted by daleyracing:
... my ? is because of the cam and the Webers is that why my timing is so different from everyones.
...

Well Dennis, considering what I just wrote, can you be sure it is that different? He, he, he …

Several factors affect a motor’s need for ignition timing, the fuel being burned has the biggest effect, but there are several other factors as well; such as the combustion chamber design, the piston’s height in the cylinder at TDC, the cylinder head port design, the intake manifold design, the exhaust system, the carburetor calibration, the camshaft design, the material the head is cast in, the vehicles gearing, the weight of the vehicle, the intensity of the ignition system. Have I forgotten anything?

Follow the old guidelines, twist the distributor at idle for fastest idle, then determine the top end on the dyno & recurve the centrifugal advance, you can’t go wrong.

In times gone by, I’ve seen Cleveland motors require between 32 and 42 degrees. I’ve had some of the guys on the Cleveland Forum tell me recently that they are running 32 degrees total timing in their motors equipped with iron heads, determined on the dyno. I assume that modern gasoline and modern camshaft grinds combine to reduce the amount of timing required. The guys running CHI heads are running right around 30 degrees total.

Your friend on the DTBB

quote:

Have I forgotten anything?

Believe it or not flywheel weight makes a differance on timing. Lighter flywheels are more sensitive to it.

That's absolutely right my friend, you can add the weight of the reciprocating assembly to the list. As a matter of fact, the weight of all the rotating parts in the drive train, including the wheel assemblies, can affect the motor's ignition timing needs. The car is a system. Which is why a chassis dyno is an invaluable tool.

your friend on the DTBB
(borrowing a co-workers computer at lunch)

Does Harbor Freight sell dynos?

quote:

Originally posted by PanteraDoug:
Does Harbor Freight sell dynos?

Nope, you have to go to like autozone for one of them.

quote:

Originally posted by PanteraDoug:
Does Harbor Freight sell dynos?

If I had one of them calibrated arses, I guess I wouldn't need one!

I found that the Webers like 38-40 degrees. Gas quality comes into play here.
I do remember that there was a limit though. There was detonation at 41-42. It shut the engine off.
I was also killing the advance springs in an
Accell dual point for some reason also.
20 degrees initial with Webers is about right.

George, thanks for your reply. What do you consider a racy camshaft? Mine is a Crower mechanical roller (level 4 on Crowers 1 to 5, 5 being a full race) with intake duration of 275 and exhaust duration of 284, .570" of total valve lift. The motor pulls about 8" of vacuum at 800 to 1000rpm. I will try to check where TDC really is.

8" of Hg vacuum at idle is pretty racy heh?

Lumpy idle, no power brakes?

I'm not a cam expert, but that cam doesn't look that radical to me. I guess its the 110 degrees lobe separation. If Crower would spread them lobes apart to 114 degrees your idle would improve, the powerband would widen, not hit so hard or drop off as quickly.

It would be a George approved powerband, lol....

On a side issue, a lot of guys experience roller failure with mechanical rollers used on the street, sometimes within 4000 miles. Mark McKeown says he can make them last, so at some point you may want to pick his brain.

your friend on the DTBB

Interesting George, I threw those numbers in dyno sim and show very little difference in power below 4500 rpm with a large drop in power above 4500rpm by going from 110 degree seperation to 114:

One brand of mechanical roller; and it escapes me right now which, has a micro hole allowing oil in the side of the roller. Guys have been having better luck with that one.

Gary

My brother had a comp cam that was out of specks by the way. After the round part of the cam, the initial part of the flat part had a slight dip. His cam was also out of spec on a couple lobes. He sent it back to Comp and they didn't know what to say. They said even though it's out of spec (their specs) but it was still ok and that if they wanted a better cam they need to go with a custom grind. He ask them if he should adjust lash for the round part or the dip. The guy had no answer. This kind of stuff is hard on solid's and I wonder how many are causing problems and people are not even checking them.

Gary

> Using a Snap-On, adjustable, digital timing light, My initial timing is at 27
> degrees. I seem to remember that the Mallory Unilite distridutor (no vaccum)
> has 24 degrees mechanical advance. The engine seems happy and will verify
> when I get it out on the road. Do these numbers seem within reason?

Does your Snap-On read out in distributor advance or crankshaft advance?
Distributor advance is half of crankshaft (measured advance) because the cam
turns at half the speed of the crank. The crank goes around twice to fire
all eight cylinders. Unless your cranking compression is low, 27 degrees
initial should kick back on the starter when hot. Mine does it at 18
degrees initial.

You want to diddle the centrifugal advance until it just barely pings
at WOT, all the way from idle to redline. Then back the static off
until it doesn't ping any more. If it's hard to start, you might have
to diddle some more to reduce the static advance and get more timing
when it's running. It'd be nice to have some sort of scope or readout
to see what the different bits are doing, but we shadetree types just
have to do it be cut and try.

Once you have the centrifugal curve set, you want as much vacuum advance
as you can get at freeway cruise, without surging. Most OEM-type canisters
only give 4-8 degrees of advance. An SBF or SBC can usually take 20 or so.
Though there is a theoretical "Maximum Best Timing", where power falls off
when you go past that point, the point has always been beyond the ping limit
of most American V8's I've played with.

Centrifugal advance is a curve (degrees of advance versus RPM). Setting
the initial advance only shifts a given curve. It does not alter the
shape. At some points, the engine's going to need more advance, at some
points less. You don't want to just back it off until it's all below the
ping limit or you'll lose a bunch of power, throttle response and fuel
economy (it might even run hotter than desired). You have to adjust the
curve to what the engine needs at worst case, which is WOT. To find the
curve you need, keep adding advance until it pings at a given RPM, then
back off. Note the advance at that point. Pick another RPM and repeat
the process several times until you have a cut at the curve you need.
Then play with the distributor cam, weights, and springs, until you
approximate the curve. You're not going to get it perfect; the best you
can do, is cross over the ping line a few times. Then you back off the
static until it doesn't ping any more. If you're lucky, the static will
be low enough the engine will start when hot (kick back on the starter).
If not, you need to either tweak the curve until you can back the static
off some or add a start retard device.

It's not a fun job. On a Unilite, the mechanical advance mechanism
is buried below the optical pick up. To alter the curve, you need to
change springs, as well as adjust the mechanical stops that limit the
maximum advance. To set the limit, you remove the Unilite plate and
vacuum advance mechanism. if so equipped. There are two allen head set
screws that screw into the side of the distributor housing to retain the
Unilite plate. They are quite small so look closely for them and make
sure not to loose them. Once the plate is out of the way, there will be
two stops, 180 degrees apart. You loosen the screws holding the stops
and then insert a the special Mallory stepped plastic "key". Each step
is marked and corresponds to 2 degree advance increments. Insert the key
to the desired stop, push the stops in and tighten the retaining screws.
Mallory has a chart that that I've included below that shows the proper
springs to use with the advance limits you've chosen.

Racers operating mostly over, say, 3000 or 4000 RPM can just pick an
arbitrary advance and lock the distributor there. Some dirt track
guys will add a device to retard the advance to kill power when conditions
get slippery (a very primitive traction control). These race engines may
detonate horribly at mid-range or below but they're never driven under load
there; just long enough to make it up to racing revs. Drag racers sometimes
just lock the advance and put up with it, hoping they don't blow a rod
through the side of the block. Not good for a street engine so you need
a good curve.

MSD makes a timing computer for this sort of thing and Crane mkaes a
distributor with a number of pre-programmed curves that can be selected
externally.

Below I've attached a previous post on Mallory Unilte distributors that
may of some use.

Dan Jones


> Car has Mallory Unilite and big Mallory coil

Does the Unilite have a vacuum can?

> It was wired so that the power came thru the stock ballast and then to 2 more
> ballasts in series.

Too much ballast. Mallory supplies a misleading instruction document that
can lead you to want to do that. If you download the more detail info from
their website or call them, they tell you different. With multiple ballast
it will have a weak spark and may not keep the plugs clean. A quick test
is to use one of the spark tester plugs (I have one).

> Mallory site says to use the stock ballast if the car came with one. Nasty
> wiring job with crimp on connectors. I rewired and soldered all the ring
> terminals. Only used the stock ballast. Seems to run fine.

There's a maximum voltage at the photoelectic eye (7 to 9 volts) that's safe.
Above that, the Unilite will work just fine but it will eventually fail.
Also, don't run solid core wires with the Unilite. They will also eventually
kill the module. Apparently the coil wire is the worst culprit and some coils
can leak back to the module when the ignition is switched off. The module
will pick up noise and produce a poor trigger signal if the wires aren't
suppressed. Also, the module is cooled by heat transfer to the aluminum
housing. There is a thin layer of white dielectric grease between the module
and the housing that helps heat transfer. The grease will eventually dry out
so it's a good idea to put in a fresh layer after a number of years.

The Unilite uses a three wire hook up. The brown wire is grounded to the
engine. Make sure you also have a good ground cable/strap between the engine
and the body. You can look at my car or I think Mike Daily has a write up
on panteraplace.com. Do not ground the brown wire from the module directly
to the frame or battery. If you do, the brown wire will become a ground for
the starter during cranking which will melt the brown wire and take out the
module. The green wire connects to the negative side of the coil. The red
wire can connect to the positive side of the coil but it's better to connect
it to the high side (12 volt) of the ballast resistor. The ballast or
resistor wire is there to limit the current through the coil and the green
wire. The red wire prefers to see full battery voltage. If you connect
the red wire to the positive side of the coil (which is also the low side of
the ballast) the engine may not start as easy especially if the battery is
low. If your car has a resistor wire rather than a ballast, you can either
hook the red wire to the positive side of the coil, or better yet, find a
place to hook it that will feed the red wire full battery voltage whenever
the key is on.

BTW, I run an MSD 6AL multi-spark box with my Unilite. The Unilite is
basically just a points replacement module so don't try to run too wide a
gap unless you run an external amplifier. If you run a spark box, the
wiring is different but Mallory has detail diagrams for those. A ballast
or resistor wire is not needed when using an external box since all the
current for the coil goes through the box rather than the module. When
used with an external box, the Unilite modules will last almost forever
because very little current goes through it. MSD suggests you leave the
ballast or resistor wire in place so it can be hooked back up should the
MSD box fail. I had that happen once and just used the MSD supplied
jumper and fired it up and drove home. Now I carry a spare MSD.

Some additional info from a web source on how to properly check the Mallory
wiring:

I often hear people ask what voltage they should have at the coil when running
a Mallory module without an external box. The standard answer is about 7 to 10
volts measured at the coil with the engine running. However, while this is easy
to measure, it is not the best thing to measure since the voltage will vary
depending on the voltage output of the alternator. What really matters is the
total resistance of the primary side of the ignition. This includes the ballast
(or resistor wire) and the primary resistance in the coil (measured with an ohm
meter between the positive and negative terminals on the coil). The ideal total
resistance is a minimum of 1.4 ohms and a maximum of about 3.5 ohms. More than
3.5 ohms is safe for the module but the spark may be too weak for optimum
performance. Use an ohm meter to measure the resistance across the ballast and
add that to the amount of primary resistance in the coil. The total should be
between 1.4 and 3.5 ohms. You may need to measure the resistance of the ballast
after it has warmed up since some ballast resistors increase in resistance with
temperature. If your car has a resistor wire rather than a ballast it can be
difficult to measure the resistance in the wire as the wire gets lost in the
harness. If so, assume that the resistance in the wire is about 1.0 ohms which
is typical.

Some coils have so much primary resistance that a ballast resistor or resistor
wire is not necessary. Mallory has two new Promaster coils that have all the
resistance built into the coil (29450 and 30450). Using these coils, no
additional resistance is needed.

Having all the resitance built into the coil has drawbacks however. The coil
will run hotter which will reduce the life of the coil somewhat. Also, high
resistance coils are not recommended for use with external boxes as the coils
will overheat and fail (sometimes even explode!).

Don't use solid core plug wires with any electronic igntion.

If you weld on the car, disconnect the module before doing so.

Still with me? Once we have the wiring verified, we should probably check
the advance curve with a dial back timing light (I've got one if you need it).
Do you have the stepped Mallory key that's used to set the stops? If not, I
should have one of those too. You may want to pick up a kit to curve the
distributor but that might wait 'til later. The mechanical advance mechanism
is buried below the optical pick up. To alter the curve, you need to change
springs, as well as adjust the mechanical stops that limit the maximum
advance. To set the limit, you remove the Unilite plate and vacuum advance
mechanism, if so equipped. There are two allen head set screws that screw
into the side of the distributor housing to retain the Unilite plate. They
are quite small so look closely for them and make sure not to lose them.
Once the plate is out of the way, there will be two stops, 180 degrees apart.
You loosen the screws holding the stops and then insert the Mallory stepped
plastic key. Each step is marked and corresponds to 2 degree advance
increments. Insert the key to the desired stop, push the stops in and
tighten the retaining screws. Mallory has a chart that that I've included
below that shows the proper springs to use with the advance limits chosen.

Advance spring selection instructions (thankfully typed in by Kirby Schraeder)

There are two basic advance curve configurations; the Straight-Line Curve
and the Hop-Out Curve. The Straight-Line Curve is used when a smooth linear
advance is required throughout the engine operating RPM. The Hop-Out Curve
is used when a lot of advance is required early and a more gradual advance
through the rest of the engine operating RPM.

1. The first step is to decide which curve will best suit your particular
application. This will all be determined by engine RPM operating range, type
of use and engine components used. For figuring Straight-Line Curve, use
steps 2 through 5. For figuring Hop-Out Curve, use steps 6 through 11.

2. In order to plot a Straight-Line Curve you must decide at what RPM you
want your advance to start and at what RPM you want your total advance to
finish. The curve in Figure 1 is an example, it starts at 1000 RPM and is
fully advanced at 2400 RPM. Plot your curve on the graph in Figure 3.

(Figure 1, 2 and 3 are all line graphs with the x-axis being engine rpm and
the y axis being degrees advance at the crankshaft.)

3. Mark off a 1000 RPM interval and count the number of degrees in that
interval. (The curve in Figure 1 of their chart has 19 degrees per 1000 rpm
interval because it starts at 1000 and ends up at 26 degrees advance at 2400
rpm. A little straight line y=mx+b math will give you the solution between
any other points.)

4. Using the Straight-Line Curve Chart, go down the Degree Column until you
come to the same number of degrees as you figured in step 3. The letters in
the Spring Column of what I sent previously will tell you which springs to
use. The springs they use in their example are A-B for 19 degrees.

The 'Hop-Out stuff' is a bunch more typing....

With quench heads, you'll not want to exceed 20 degrees total advance.
Initial will be around 16 degrees with a hot cam, with 10 at the distributor
(10 distributor = 20 crank degrees since the cam and distributor run at half
the crank speed) for a total advance of 36 degrees.

Mallory Unilite advance spring selection Table 1 shows:

Degrees Springs

7 degrees or less E-F
8 1/2 E-E
9 A-F
9 1/2 B-F
10 C-F
11 D-D
12 1/2 C-D
13 1/2 C-C
14 A-D
15 B-C
16 A-C
18 B-B
19 A-B
20 A-A
20-26 B
28 up A

Springs
A Red
B Blue
C Dark Green
D Bronze
E Black
F Light Green
G Orange
H Light blue
I Yellow
J Pink
K Silver
L White

If all this looks like too much work, there's always the MSD timing computer.
The timing computer locks out the distributor's mechanical advance and
replaces it with whatever you dial in. To specify the curve (a line really),
you enter a start point, a maxiumum value, and a slope. Added features are
20 degrees start up retard (for easy cranking on high compression engines)
and selectable high speed retard. Can also be used with MSD's adjustable
initial advance knob doohickey, too. It would make it very easy to dial in
the curve, then you could remove the unit and have the distributor re-curved
on a machine to match the computer curve. You would lose the start-up and
high speed retard, though.

Dan Jones

Dan, WOW!

Thanks for the info.

>>Does your Snap-On read out in distributor advance or crankshaft advance?

I'm not sure. I'll have to check that out.

With any luck I'll get the car out tonight and see how things work out.

quote:

Originally posted by comp2:
...My brother had a comp cam that was out of specks by the way. ...

After I wrote my reply to BD this AM I realized I should haven mentioned that a cam needs to be degreed during istallation. If the cam indexing is a few degrees retarded, a cam like this can become more lumpy than it was designed to be, because the intake valve is closing a few degrees later than designed. The designer of this cam is trying to walk a line between a street cam and a race cam, and so the timing events are pushing the envelope of drivability, which in turn requires precision in the indexing of the cam to reach the designers goals. Based on that good ol' yellow book about Ford Performance, originally written in the '70s, the engine loses drivability if the intake valve closing event (measured at 0.050") is later than 40 degrees ABDC (memory?).

So BD, that's something I wanted to pass along, if your cam wasn't degreed during installation, it may help to do so. If it is found to be off, especially in the retarded direction, it would be advantageous to advance the cam to
crower's spec with a multi-indexed timing set.

your friend on the DTBB

The problem with the comp cam wan't simply a degree problem. Lift was off.

George - To answer your questions, I degreed the cam in myself using a cam degree wheel. The cam card says that the intake valve closes 43 degrees ABDC.

So, the cam was desgned to have poor idle quality.

Did you check the intake vacuum when you had the static timing advanced to 32 degrees? my advice is to set it for optimum intake vacuum, regardless of where it ends up. Dialing the carb in will be easier, the motor will pull better in the lower rpm range too.

your friend on the DTBB

Do you have all the cam specs? That is very close to the cam in my 434 and it has shown very very good idle.

Gary

Gary, whats a lopey cam in a 351 will be mellowed out in a 434.

George

The cam specs are in addition to what I have already mentioned, intake opens 11.0 BTDC, intake closes 43 ABDC, exhaust opens 56 BBDC and exhaust closes 8 ATDC. The Crower part no. is 15480.

quote:

Originally posted by george pence:
Gary, whats a lopey cam in a 351 will be mellowed out in a 434.

George

George that's obvious but will still have similar charachteristics.

BD, Thanks. I will put those specs in desktop dyno later today to compare them.

Gary

BD,
I love playing around in desk top dyno. I don't know how well what we see translates into the real world. I can tell you when I used desk top dyno to check cams for my 434 build it came out very very close!

I have some info here for comparison. I think the comparison would be as much for entertainment value. It is hard to learn anything from 2 different engines. If you have identical engines on identical dyno's then a single change can be relevent. Beyond that much is speculative. Just the same this is interesting.

First my engine is a 434 with several differences. As George said the increase in cubes will tame an agressive cam some what. I have not ran my engine in the car but the engine builder says it idles like a factory engine; kind of a sleeper almost. Throttle reponse is imediate and agressive.

That being said, I ran your cam and my cam in the DD just to see the difference. I used some general 351 cleveand specs so the HP number are meaning less except for the fact that the only difference between the two is the cam. DD had your cam so I ran withy their specs (which matched what you gave me). Here was the numbers for your cam:



Here are the numbers for my cam:



Here is the same engine compared with the cams being the only difference:



Your cam no doubt made more power then mine; epsecially at lower rpm which is where I was looking for power. One difference comes to mind here. Your cam has a bit more agressive ramp rate which I am guessing will be harder on solid lifters (lifters in general). It is very similar to mine with some differences.

This makes for some interesting "internet theories"!

I will let you know how mine runs when I get it in the car.

Gary

Yours is the solid line and mine is the dotted line.

One interesting thing is you have more valve overlap. This is generally more helpful in higher rpm but...largely do to some other variations, your increase in power is in the lower rpm band (which is good).

G

Gary, since you did actually dyno your engine as well, how close did it come to the Desk Top Dyno?
Can you by anychance overlay the real one over the Desk Top?
The Desk Top has created a lot of problems for me personally.
The problems mostly being the reaction to the results, which generally speaking, can be termed up in the scientific statement, "bull shit".
Not being one to be able to have a real dyno in the garage, I try to refrain from showing the data sheets.
I think the problem may also be partially that when I want to buy something it is worth all the money in the world. When I want to sell something, apparently it is next to worthless.

PD,

Amazingly close actually. I made the following dyno sheet when we were building the engine 6 monhs ago. Peak hp was just below 500. I could not break 500. Tq was a little over 520. This graph actually shows the same engine, same cam except one is the 434 (actualy 427 with no overbore) and the dotted line shows the same in a 351 configuration. Shows the difference in cubes everything else the same.

http://www.rc-tech.net/cars/panttransam/1905/351v400.jpg

This is the actual dyno run:

http://www.rc-tech.net/cars/panttransam/1905/dyno2.jpg

He has one run not in there he made 494 hp. The first graph lookes more arched but it is how it is spread out. If you plot them they are very very close. Bigest difference is the actuall engine made more torque down low. It come out of the gate at 2K rpm at more then 420lbs tq.

One thing that may be a little different though is the head flow. I used CHI head flow for the DD (desktop Dyno). The 3v heads flowed less at lower lift then the 2v but there was more material around the exhaust valves CHI did not remove so the builder worked on that. I wish he had re-flowed the heads but that could be adding a little tq in the lower rpm band and maybe even across the board. No way to know without comparing both though.

Either way HP was within 5 and tq was within 15.

Gary

I didn't look at that right. Tq on the DD was up high down low too.

G

I think that is pretty close. I plugged in all the numbers to my DD for 357ci and it came up as 563hp at 6300rpm, 450lb-ft torque at 5000.
No one believes me. I don't believe myself sometimes, sigh.

Do you want to send me the numbers and let me see what I get?

I'm ok with it. Let sleeping dogs lie.