Intake Manifold, Carb

hello, a 4v intake will fit on 2v heads to start. a dual plane works great for street, idle to 55oo rps while a single plane is 1500 to 6200 rpm. either way the heads will help with the low end but you going to loose some upper band power. if the car is driven maily on the street, in my opinion go with the dual plane. also my want to take a look at the cam and see if wirk with the intake band.

I've replaced my 4-V heads with the 2-V heads and the correct intake to use is the Weiand 2-V Accelerator intake manifold. It bolts right on and is compatible with whatever Holley you prefer to use. I have tried the 600 cfm (works fine), but with my particular setup I am using the 650 cfm double pumper and am very happy with the results.

Al, What are the specs on the cam you are using? As I understand it, this may determine whether a single or dual plane manifold will work best. Mark

quote:

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Originally posted by Al:
I've replaced my 4-V heads with the 2-V heads and the correct intake to use is the Weiand 2-V Accelerator intake manifold. It bolts right on and is compatible with whatever Holley you prefer to use. I have tried the 600 cfm (works fine), but with my particular setup I am using the 650 cfm double pumper and am very happy with the results.

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This combo works in my design! And revs forever! Edlebrook Torker II, Single Plane. "Cloverleaf" carb pad if you can find it, or have a choice. Top it with a 4 Hole, 1 inch thick carb spacer. Align the 4 holes for best, then Ink, Scribe, grind and smooth the cloverleafs to match with spacer(no interferance). This will creat a little more volocity, at any RPM, than a "open Planum", single plane manifold. I do NOT recommend, nor use dual plane manifolds! That is only my opinion, take it for what it may be worth! And I would NEVER put a 4 barrel manifold on 2 barrel heads!! Yes, it would work, but would never run optimum because of the "WAllS" created when LARGE ports sit on top of small ports, facing the direction of gas flow. Thus causing flow ristricting TURBULANCE! Regards, Marlin.

[This message has been edited by MARLIN JACK (edited 04-25-2003).]

> I know this has been covered in the past but... what is the preferred
> intake manifold for a street performance car? I am replacing the 4V heads
> with Aussie 2Vs and purchased the car with an Edelbrock 1411 (750 cfm)
> carb on it.

Easy answer: Weiand Xcelerator 2V, providing you port-match it to the
Aussie heads. The intake ports are larger than the hea ports, so you
must port-match for best results.

> a 4v intake will fit on 2v heads to start.

4V port intakes will bolt up to 2V heads and back in the early 1970's,
before dedicated 2V intakes were available, Ford even recommended it
(my brother-in-law ran such a set-up) but today there are many 2V intakes
that are designed for 4 barrel carbs that will do a better job. I'll
cover several of the more popular choices briefly below.

The Offenhauser Dual Port 2V is dual port design which is not the same
as a dual plane. The dual port design has the runners split into top and
bottom sections with the plenum split fore and aft (rather than the usual
side-to-side). It's essentially two single plane intakes stacked on top of
each other with the 4 barrel carb primaries feeding the longer path lower
runners and the secondaries feeding the shorter path upper runners. It's
an interesting concept but the packaging required to fit within a carb
intake envelope does compromise the design. The Offy Dual Port has the
reputation of being a good low to mid range intake with excellent throttle
response and fuel economy (probably the best cruise fuel economy based upon
BSFC tests performed by David Vizard). It's not a high rpm intake but
Offenhauser says you can trim the dividers back at the head flange to pick
up some top end power. Kirby Schrader replaced the Holley Street Dominator
intake on his Detomaso Longchamp coupe (Aussie open chamber 2V engine, C6
automatic, around 3800 lbs) for an Offy Dual Port. He reported the low end
picked up noticeably with no loss of top end (probably cam and carb limited
in his case).

The Edelbrock Performer 2V (a.k.a. Edelbrock F-351 2V, p/n 2750) is a
low rise dual plane with Holley carb bolt pattern and ports that are
approximately the same size as 2V cylinder head ports. A good choice
for heavier vehicles with taller gears and automatic transmissions with
moderate stall speed converters. Makes a good truck intake with say a
268H Comp cam and a set of tri-y truck headers.

The Holley Street Dominator (p/n 300-12) is a low rise, open plenum,
single plane with Holley carb bolt pattern. The Street Dominator was
designed as an economy type single plane and was advertised as a
universal fit for both 2V and 4V but the ports are actually smaller
than a stock 2V cylinder head intake port. The plenum is also smaller
than the other single planes. One unique feature is that the plenum
opening is trapezoidal and will directly mount a stock Motorcraft 4300D
spreadbore carb. I don't like this intake for any application. The
small ports and plenum choke off the top end and the Edelbrock Performer
and Offenhauser Dual Port are better ...

The Weiand X-Celerator 2V (p/n 7516) is a medium rise single plane with
Holley carb bolt pattern. It's an excellent choice for lighter vehicles
with manual transmission, decent gearing, and/or a higher stall converter.
One important thing to note about the Xcelerator is that the ports are
larger than the 2V head ports. It's essentially a pre-ported intake and
requires the heads be match ported to the intake. Also note that when
Holley purchased Weiand, they screwed around with the intake manifold
names and started calling the Xcelerator a Stealth, a name that had been
reserved for high rise dual planes.

Offenhauser Port-o-Sonic 2V (p/n 6122 and 6123) is a single plane, open
plenum, intake much like the Weiand Xcelerator 2V. The primary difference
is that the ports are the same size as a 2V head port. I have no direct
experience with Port-o-Sonic so I can't comment on how well it works,
though one engine builder I talked to said he had to work the plenum area
over for best results.

There are also several 2V intakes from Australia. There are several very
tall single plane intakes (Active, TFC, and Terry Parker's Funnelweb). All
are very much like a Roush high port intake but with 2V ports. Then there's
the Street Torker from Redline (http://www.redlineauto.com.au/) which looks
just like a Holley Strip Dominator but with 2V ports. One interesting feature
is the Street Torker will directly mount a Carter Thermo Quad or Rochester
Quadrajet spreadbore carb, in addition to the usual Holleys and AFB's. If
you want to get exotic, Redline also offers 2V Weber intakes for both IDA
and IDF carbs and there are supercharger intakes.

> a dual plane works great for street, idle to 5500 rpm while a single
> plane is 1500 to 6200 rpm. ... if the car is driven maily on the street,
> in my opinion go with the dual plane.

A lot of factors come into play but given the Panteras relatively light
weight, 4.22:1 final drive ratio, close ratio 5 speed, and moderate 2V
head port size, and the choice of intakes available, the single plane
Weiand Xcelerator 2V is the way to go. Works well down low and is worth
quite a lot of power, even on a relatively mild engine, over a Performer.
A guy I know drag strip tested both the Edelbrock Performer 2V and the
Weiand Xcelerator 2V on his street Mustang which had a mild 351C with open
chamber 2V heads. With an Edelbrock Performer 2V, it ran 14.80s shifting
at 5500 rpm. Switching to the Weiand Xcelerator 2V, with no other changes,
put the car into the 13.20's. That's a huge change and shows the intake
was the bottleneck in his combo. The engine currently in my Pantera is
topped off by a Weiand Xcelerator 2V intake. You can see it at:

http://www.panteraplace.com/Pantera%20Pics/Weiand%20intake.jpg

With a drop base air cleaner and a 2 1/4" tall K&N air filter (barely
clears the choke plate when open) the Weiand fits under my stock '74L
engine screen. If you don't mind altering the screen or running without
it, it will work even better with a 1" or 2" tall spacer and a non-drop
air cleaner base. The rest of the engine combo consists of pocket-ported
and port-matched Aussie closed chamber 2V cylinder heads, Hedman 1 3/4"
Pantera headers (a direct match for 2V exhaust ports), a Holley 735 CFM
carb, and a mild custom cam (218/222 @ 0.050", 0.530" lift, 110 degrees
LSA). Even with the big Holley, the Xcelerator works fine down low. I
can put it in 5th gear and it will pull smoothly from just off idle, say
1000 rpm or so. Excellent throttle response and pulls to 6000 RPM
(limited primarily by the mild cam) and gets 20 mpg on the highway (without
vacuum advance).

You lose quite a bit of CFM with 2V heads, compared to 4V, but pick up
port velocity. To get some of the CFM back, I suggest the following.
Use oversize 2.1" diameter intake valves (available from Ferrea), 1.65"
diameter (same as stock 2V) exhaust valves with undercut stems and a 30
degree backcut (to aid low lift flow). Do a good bowl port (blend the
area under the valve seats, narrow the guides, and port match the intake
ports to the Weiand Xcelerator 2V intake manifold. It's also important
to unshroud the valves as the Aussie chambers have very tight chambers.

> Al, What are the specs on the cam you are using? As I understand it,
> this may determine whether a single or dual plane manifold will work
> best.

With the Aussie 2V heads, you'll want something with a single pattern and
110 LSA. The mildest cam I would recommend is a hydraulic flat tappet
from Ultradyne that specs out at:

221/221 degrees @ 0.050" (276/276 advertised), 110 LSA, 0.524"/0.524" lift

On the upper end, for a street driven Pantera, with Aussie heads, I'd
recommend a Comp 282S solid lifter flat tappet cam (part # 32-238-4):

236/236 deg @ 0.050" lift, 110 LSA, 0.570"/0.570" lift (minus 0.022 lash)

Charlie McCall is running this cam in his Pantera and is quite happy with
it.

Dan Jones

Wow, what a wealth of information! Thanks to all for the help. I am not very experienced with engine building, how does port matching work? I understand the concept, but what is the actual process? Can the slightly above average mechanic do it?

quote:

---

Originally posted by Dan Jones:
> I know this has been covered in the past but... what is the preferred
> intake manifold for a street performance car? I am replacing the 4V heads
> with Aussie 2Vs and purchased the car with an Edelbrock 1411 (750 cfm)
> carb on it.

Easy answer: Weiand Xcelerator 2V, providing you port-match it to the
Aussie heads. The intake ports are larger than the hea ports, so you
must port-match for best results.

> a 4v intake will fit on 2v heads to start.

4V port intakes will bolt up to 2V heads and back in the early 1970's,
before dedicated 2V intakes were available, Ford even recommended it
(my brother-in-law ran such a set-up) but today there are many 2V intakes
that are designed for 4 barrel carbs that will do a better job. I'll
cover several of the more popular choices briefly below.

The Offenhauser Dual Port 2V is dual port design which is not the same
as a dual plane. The dual port design has the runners split into top and
bottom sections with the plenum split fore and aft (rather than the usual
side-to-side). It's essentially two single plane intakes stacked on top of
each other with the 4 barrel carb primaries feeding the longer path lower
runners and the secondaries feeding the shorter path upper runners. It's
an interesting concept but the packaging required to fit within a carb
intake envelope does compromise the design. The Offy Dual Port has the
reputation of being a good low to mid range intake with excellent throttle
response and fuel economy (probably the best cruise fuel economy based upon
BSFC tests performed by David Vizard). It's not a high rpm intake but
Offenhauser says you can trim the dividers back at the head flange to pick
up some top end power. Kirby Schrader replaced the Holley Street Dominator
intake on his Detomaso Longchamp coupe (Aussie open chamber 2V engine, C6
automatic, around 3800 lbs) for an Offy Dual Port. He reported the low end
picked up noticeably with no loss of top end (probably cam and carb limited
in his case).

The Edelbrock Performer 2V (a.k.a. Edelbrock F-351 2V, p/n 2750) is a
low rise dual plane with Holley carb bolt pattern and ports that are
approximately the same size as 2V cylinder head ports. A good choice
for heavier vehicles with taller gears and automatic transmissions with
moderate stall speed converters. Makes a good truck intake with say a
268H Comp cam and a set of tri-y truck headers.

The Holley Street Dominator (p/n 300-12) is a low rise, open plenum,
single plane with Holley carb bolt pattern. The Street Dominator was
designed as an economy type single plane and was advertised as a
universal fit for both 2V and 4V but the ports are actually smaller
than a stock 2V cylinder head intake port. The plenum is also smaller
than the other single planes. One unique feature is that the plenum
opening is trapezoidal and will directly mount a stock Motorcraft 4300D
spreadbore carb. I don't like this intake for any application. The
small ports and plenum choke off the top end and the Edelbrock Performer
and Offenhauser Dual Port are better ...

The Weiand X-Celerator 2V (p/n 7516) is a medium rise single plane with
Holley carb bolt pattern. It's an excellent choice for lighter vehicles
with manual transmission, decent gearing, and/or a higher stall converter.
One important thing to note about the Xcelerator is that the ports are
larger than the 2V head ports. It's essentially a pre-ported intake and
requires the heads be match ported to the intake. Also note that when
Holley purchased Weiand, they screwed around with the intake manifold
names and started calling the Xcelerator a Stealth, a name that had been
reserved for high rise dual planes.

Offenhauser Port-o-Sonic 2V (p/n 6122 and 6123) is a single plane, open
plenum, intake much like the Weiand Xcelerator 2V. The primary difference
is that the ports are the same size as a 2V head port. I have no direct
experience with Port-o-Sonic so I can't comment on how well it works,
though one engine builder I talked to said he had to work the plenum area
over for best results.

There are also several 2V intakes from Australia. There are several very
tall single plane intakes (Active, TFC, and Terry Parker's Funnelweb). All
are very much like a Roush high port intake but with 2V ports. Then there's
the Street Torker from Redline (http://www.redlineauto.com.au/) which looks
just like a Holley Strip Dominator but with 2V ports. One interesting feature
is the Street Torker will directly mount a Carter Thermo Quad or Rochester
Quadrajet spreadbore carb, in addition to the usual Holleys and AFB's. If
you want to get exotic, Redline also offers 2V Weber intakes for both IDA
and IDF carbs and there are supercharger intakes.

> a dual plane works great for street, idle to 5500 rpm while a single
> plane is 1500 to 6200 rpm. ... if the car is driven maily on the street,
> in my opinion go with the dual plane.

A lot of factors come into play but given the Panteras relatively light
weight, 4.22:1 final drive ratio, close ratio 5 speed, and moderate 2V
head port size, and the choice of intakes available, the single plane
Weiand Xcelerator 2V is the way to go. Works well down low and is worth
quite a lot of power, even on a relatively mild engine, over a Performer.
A guy I know drag strip tested both the Edelbrock Performer 2V and the
Weiand Xcelerator 2V on his street Mustang which had a mild 351C with open
chamber 2V heads. With an Edelbrock Performer 2V, it ran 14.80s shifting
at 5500 rpm. Switching to the Weiand Xcelerator 2V, with no other changes,
put the car into the 13.20's. That's a huge change and shows the intake
was the bottleneck in his combo. The engine currently in my Pantera is
topped off by a Weiand Xcelerator 2V intake. You can see it at:

http://www.panteraplace.com/Pantera%20Pics/Weiand%20intake.jpg

With a drop base air cleaner and a 2 1/4" tall K&N air filter (barely
clears the choke plate when open) the Weiand fits under my stock '74L
engine screen. If you don't mind altering the screen or running without
it, it will work even better with a 1" or 2" tall spacer and a non-drop
air cleaner base. The rest of the engine combo consists of pocket-ported
and port-matched Aussie closed chamber 2V cylinder heads, Hedman 1 3/4"
Pantera headers (a direct match for 2V exhaust ports), a Holley 735 CFM
carb, and a mild custom cam (218/222 @ 0.050", 0.530" lift, 110 degrees
LSA). Even with the big Holley, the Xcelerator works fine down low. I
can put it in 5th gear and it will pull smoothly from just off idle, say
1000 rpm or so. Excellent throttle response and pulls to 6000 RPM
(limited primarily by the mild cam) and gets 20 mpg on the highway (without
vacuum advance).

You lose quite a bit of CFM with 2V heads, compared to 4V, but pick up
port velocity. To get some of the CFM back, I suggest the following.
Use oversize 2.1" diameter intake valves (available from Ferrea), 1.65"
diameter (same as stock 2V) exhaust valves with undercut stems and a 30
degree backcut (to aid low lift flow). Do a good bowl port (blend the
area under the valve seats, narrow the guides, and port match the intake
ports to the Weiand Xcelerator 2V intake manifold. It's also important
to unshroud the valves as the Aussie chambers have very tight chambers.

> Al, What are the specs on the cam you are using? As I understand it,
> this may determine whether a single or dual plane manifold will work
> best.

With the Aussie 2V heads, you'll want something with a single pattern and
110 LSA. The mildest cam I would recommend is a hydraulic flat tappet
from Ultradyne that specs out at:

221/221 degrees @ 0.050" (276/276 advertised), 110 LSA, 0.524"/0.524" lift

On the upper end, for a street driven Pantera, with Aussie heads, I'd
recommend a Comp 282S solid lifter flat tappet cam (part # 32-238-4):

236/236 deg @ 0.050" lift, 110 LSA, 0.570"/0.570" lift (minus 0.022 lash)

Charlie McCall is running this cam in his Pantera and is quite happy with
it.

Dan Jones

---

And all this time I thought the strip dominator was the way to go!!?

The Strip Dominator is for 4V heads and is a great manifold. Don't confuse it with the Street Dominator for 2V heads. The intakes discussed above are for 2V heads. Don't make the mistake of assuming that because a particular intake works well in a 2V version, it will work well in a 4V version. The Weiand Xcelerator 4V is a dog on 4V heads but the Weiand Xcelerator 2V is great on 2V heads. I know of at least on person that got better results on a 4V engine using the 2V Xcelerator instead of the 4V.

Dan Jones

> Wow, what a wealth of information! Thanks to all for the help. I am
> not very experienced with engine building, how does port matching
> work? I understand the concept, but what is the actual process? Can
> the slightly above average mechanic do it?

It's fairly simple. The intake ports of the Weiand are larger than
the 2V head ports. Port matching entails opening up the head ports
to match the intake ports using a rotary die grinder with a coarse
stone or a cutter. You can use an aftermarket intake manifold gasket
set (the two-piece kind, not the one-piece turkey pan) as a guide or
make a template that matches the intake manifold ports. Spray some
dye-chem or Prussian blue around the head ports, bolt the template
in place, and scribe the desired opening. Use the die-grinder to
grind out to the scribe lines. Go several inches into the port so
the transition angle is shallow.

This is best done with the heads off the engine but I have done it
on an assembled long block by sealing off the engine so no metal
shavings could get down in the engine. That's easier said than done.
I made a template to cover the lifter valley, stuffed the ports and
clayed them shut (half way down the port), and had a helper run a
shop vacuum while I did the grinding. In retrospect, it might have
been just as easy to pull the heads but it would have cost a set of
head gaskets.

Dan Jones