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I am planning on rebuilding my Cleveland to a 377cui. I plan to use it for limited regular driving, track days and some ORRs. I'm thinking of a 2500 to 6500 power band with a 7000+ red line. I plan to use closed chamberd 4v heads,roller rockers, Strip dominator manifold. I would like to get 500 to 525 HP.

Using 4V heads, will stuffing the ports be benificial? At what displacement does this become counter productive? Is it practicle to regrind the existing crank and use chev rods or should I buy a stroker crank? Cast or Forged? Billett main caps? I tend to lean towards a hyd. roller cam. Suggestions.

I don't see much written about gear driven cams, are there any quiet ones for the Cleveland?

Would a 393 hold well considering my RPM requirements?

Thanks Mark 5481 & 5461
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Originally posted by ehpantera:
...Using 4V heads, will stuffing the ports be benificial...

Only if you are employing an intake manifold designed for stuffed ports like the Parker Funnel Web. With the strip dominator, no. I personally like a good flowing dual plane manifold for road racing, better pull out of tight corners.

...At what displacement does this become counter productive...

Its necessary & beneficial for any displacement when you are employing the Parker FW. I know of a 427 Clevor using iron heads with stuffers and the Parker Funnel Web making 750 bhp at 7200 rpm. You can bet the heads are ported quite a bit. The iron 4V head is a good head, but not well understood these days. The 4V port is not as big as the entrance would lead you to believe. But if you're going to fill the bottom of the port, that loss in cross-section has to be made up somewhere else. this is stuff you don't normally hear about.

...Is it practicle to regrind the existing crank and use chev rods or should I buy a stroker crank...

Stroker displacements are quoted assuming a 0.030" over bore. 377 = 3.70" stroke, 383 = 3.75" stroke, 393 = 3.85" crank. The 3.75" & 3.85" cranks are available over the counter, the 3.70" crank is an offset-ground oem cast iron crank. I'm not a big fan of stroker kits & street tires. But whatever your plans, the over the counter crank gives you the option of selecting a forged steel version, which I think makes sense in your application. Consider a sportsman crank.

...Cast or Forged...

Since you have a 7000 rpm goal and since you plan to run Open Road Races I say buy the extra insurance and use the forged sportsman crank.

...Billett main caps...

Cleveland caps are not a weak link. I would consider that over kill in your application if the block has four bolt mains. The ProGram caps are used by builders to convert 2 bolt main blocks into 4 bolt mains, they make perfect sense in that application.

...I tend to lean towards a hyd. roller cam. Suggestions ...
Adjusting valve lash in the Pantera engine bay is a bit like laying on a bed of nails. It looks painful but everybody will assume you are a holy man! Hydraulic roller lifters are heavy and pose a challenge to run at higher rpm. To do that with the Z06 'Vette Chevy resorted to titanium valves and bee hive valve springs. Achieving those RPMs will be easier with a solid roller. A solid roller grind with "street lobes" (similar to hydraulic roller lobes) and bushing type tappets can be configured to survive street use and will not require any more adjustment than a hydraulic roller.

...I don't see much written about gear driven cams, are there any quiet ones for the Cleveland...

Dunno. They sound cool in someone else's car. But they'd be a pain in the arse to live with. I've never seen a race team run a gear drive, I've always assumed this is because gear drives consume more horsepower than chain drives. I recommend a RollMaster timing chain set.

...Would a 393 hold well considering my RPM requirements...

I'd recommend a 383. I wouldn't go bigger than 3.75" stroke due to rod to stroke ratio and piston speed.

Use a very good set of I beam con-rods, use endurance style racing pistons (stronger than drag pistons, lighter than street pistons), you'll want a lightened crank, a light weight flywheel, a good quality balancer (Romac or ATI) and dynamically balance the reciprocating assembly. Be sure to set the oil system up properly too. The more precise you can build the motor, the more durable it will be. Details like cc'ing each combustion chamber & piston clearance to insure identical compression ratios in each cylinder will stress the motor less and help it survive. Tuning the motor as precisely as possible (i.e. on a dyno) is also a necessity to help the motor stress itself as little as possible and survive hard use.

cowboy from hell
Last edited by George P
I'm going down this same road. I have just received back my heads, 4V closed chambers, Manly Heavy duty Stainless Valves with hard seats on the exhaust, chevrolet beehive big block springs, ISKY P/N 175-A, Will be running a Dual pattern cam with approx 6-10* on the exhaust, roller Hydralic. Check out these posts!
I'm going forged crank 377, the extra 20 ci will help the volacity of air on the intakes for the heads.
If I don't have a 4 bolt block I'll more than likely go with an Aussie block and have it machined for splayed caps.
Shooting for 500HP on pump gas.

Let me know how it goes, Mark

Right now I'm collecting as much info as I can. After reading the articles iron vs aluminum heads it might just change my plan to use stuffed 4v heads. We'll see where the budget goes.

Initially I want a strong bottom end that can support more hp and RPM. That way if I choose to go for more power I won't have to totally rebuild the short block again.

Would hope to have this done by late spring.
Originally posted by SICK CAT:
...forged crank 377...

Mark, you may want to refer to that motor as a 383, or mention you're using a 3.75" stroke crankshaft. Folks will assume you're using an off set ground iron crank when you call it a 377.

Originally posted by ehpantera:
...Initially I want a strong bottom end that can support more hp and RPM. That way if I choose to go for more power I won't have to totally rebuild the short block again...

Thumbs up on that plan Mark.

take care, George
Stuffing means that the floor of the intake and exhaust ports is raised by putting a piece of metal of the appropriate thickness in the bottom of the ports. Also available are sheetmetal tongues ( they look like a gasket with a tongue sticking out) that do approximately the same thing but not as well, according to some.

Because of the size of the ports the gases flowing through go at a slower speed than in a smaller port. See my posting iron vs aluminum heads.
5461 5481
Just need a roller hydralic cam? My shop suggests a dual pattern hydralic roller cam with 6* to 10* more on the exhaust. Any advise as this is the Next task!
This is off this site, for a 377 ci Cleveland:

Combo 10

We saved the juiciest Combo for last. This engine has a 3.75-inch stroker crankshaft that takes it out to 377 cubic inches. It is hard to believe how significantly 20 cubic inches can transform an engine but Clevelands respond exceptionally well to this bore and stroke configuration. The extra displacement draws on the intake ports harder, boosting port velocity, while the longer stroke mechanically increases torque production. The results are clear: equipped with an 825 Demon carburettor, a relatively mild Isky 238-degree (at 50-thou) solid roller camshaft, a CHI single plane manifold and a pair of KEC CNC ported CHI 3V heads, this stomper punched out 528hp at a modest 6000 rpm and a massive 498 Ibs/ft of torque. With an average of 466 Ibs/ft of torque it leaves the standard stroke engines in its wake. Combo 10 also achieved the highest horsepower average of 424. Stroker bottom end kits for Clevelands are readily available and cost effective. This very driveable 377 is also happy on premium unleaded and would propel most well set up Fords into the 10-second zone. It seems you really can't beat cubes!

Also these tabs go down the same line's; &

Sorry if there was any confusion on ci vs stroke, although this ought to be ample power to hunt down the newest exotics on the top end?

Last edited by sickcat
I've got the 4v heads on my Pantera right now. They have giant sewer type ports, but actually dont flow that well. Large ports dont necessarily mean good flow. Remember, these heads were designed in the late sixties, and were good at the time, but pale compared to the higher tech heads available now. The 4v heads are notorious for soft bottom end and midrange power. The 4v heads have 270cc ports, but dont flow as much as the 185cc, 208cc, and 225cc aluminum heads offered by CHI. The ports are obviously smaller, but by design they actually flow more, and more importantly, have a much higher intake velocity. This is what will really wake the motor up. I'm going with the 225cc heads on my 408 Cleveland, as well as their intake. Check them out at

Here's the math:

Radius Squared x Pi = Area of a circle

Radius = Bore/2

Cylinder Radius Squared x Pi x Stroke x Number of Cylinders = Displacement


(Cylinder Bore/2) x (Cylinder Bore/2) x Pi x Stroke x Number of Cylinders = Displacement

Radius of a 4.030" (30/1000 over) cylinder is 1/2 of the bore = 4.030/2 = 2.015"

Radius Squared = 2.015 x 2.015 = 4.060

Pi = 3.14159

4.060 x 3.14159 x 3.70 x 8 = 377.5 cubic inches.

4.060 x 3.14159 x 3.75 x 8 = 382.6 cubic inches

4.060 x 3.14159 x 3.85 x 8 = 392.8 cubic inches

4.060 x 3.14159 x 4.00 x 8 = 408.1 cubic inches

cowboy from hell
Last edited by George P
I have a question in relation to the cam. On the solid roller cam I run in my Drag race 460 I use a bronze gear on the distributor.The life of this gear is about one season then throw it away.
I am concerned with this longevity in a street motor. Do the Hydralic/solid roller cams you are talking about need a bronze gear or can they grind the cams out of the same material as the 5.0 mustang rollers so you can use a oem material gear?
My experience in relation to adjustment on our 460's is after a couple of races at the beginning of the season the valves pretty much stay put. We check them weekly as preventive maintenance but rarely have to adjust them.
I would have no problem running a solid roller on the street its just the dist gear I would be concerned with.
Originally posted by accobra:
...I come up with the same formula at 3 different websites...


Or ...radius (2) x TT (3.14) x Stroke (3.75) x (8) cylinders = 376.99...

OK Ron, I think I understand what your having trouble with.

Your math here is absolutely correct. A standard bore with a 3.75" crank is ~377 cubic inches.

However, the industry refers to a motor with a 3.75" crank as a 383, which is my point. When quoting the displacement of a stroker the industry assumes the motor is 0.030" over bored.

A Cleveland motor with an offset ground oem Cleveland crank, 3.70" stroke, has always been referred to as a 377. This is again because the industry assumes the block will be bored 0.030" over. If the block were standard bore, it would only be ~372 cubic inches.

Are we on the same page now?

cowboy from hell
Last edited by George P
Originally posted by Pittcrew:
...I would have no problem running a solid roller on the street its just the dist gear I would be concerned with...

Brooke you are aptly concerned about the bronze gear. I would not recommend anybody installing one in their motor. Unless you really like taking your motor apart frequently to remove the bronze metal shavings.

There are steel gears on the market for camshafts ground on a steel core (most roller cams) and there are iron gears on the market for camshafts ground on an iron core (flat tappet cams and Comp Cams retro-fit hydraulic roller cams). The quality of the gears on the market is variable, I wouldn't recommend anybody using a gear they picked up from Auto Zone. I haven't heard anything bad about the gears being sold by Crane Cams.

cowboy from hell
Last edited by George P
There are two steel distributor gears available for 351C (same gear as the

1. Ford Motorsport Steel Gear
P/N M-12390-J (1.421" OD, 0.531" ID, for 351C) in the FRPP catalog.
From page 105 of the 2005 FRPP catalog: "Steel gears are compatible with
billet steel camshafts (hydraulic roller type)". Comp Cams also claims
the Ford gears are compatible with their -8 austempered ductile iron
hydraulic roller cam cores (Comp also uses the -8 cores for some solid
street roller cams but uses steel cam cores for race solid rollers).
According to MSD, the Ford mild steel distributor gears (as fitted to
engines with factory hydraulic-roller-cams) are softer than the common
ductile iron gears, but harder than bronze. MSD also claims that Chevy
uses a harder cam core for it's factory hydraulic rollers and uses cast
iron gears but that its gears don't last as long as the Ford gears.
Some 5.0L Ford racers have used the Ford gear on steel cam cores without
incident but Ford does not recommended it.

2. Crane Steel Gear
Crane has a coated steel gear which they claim is compatible with induction
hardened or carburized steel roller cores, as well as iron flat tappet cores.
Their website refers to them as "specially coated and processed steel
distributor gears using either cast flat faced lifter or steel roller
camshafts". They list two part numbers for 351C distributors:

52970-1 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.500" shaft diameter
52971-1 Ford V-8 70-82, Boss 351-351C-351M-400 for 0.531" shaft diameter

Crane does not recommend the use of their gears on camshafts that have been
previously run with other types or materials of gears. Comp did not recommend
this gear on their -8 cores. I'm told but have not verified that Crane's
earliest steel gears were made like the Ford gears but their new gears are
different. We used this gear on a 408C recently with a steel cam (hydraulic
roller) from Crane.

Dan Jones

Both your calculations are correct Big Grin

The difference is George uses an overbore of 0.030", whereas Ron you have assumed a stock 4.00" bore engine. If you increase your bore to a 'standard stroker' at 30 oversize it is a 383 CI. The extra 30 thousands accounts for the extra 7 CI.
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