500 HP 351C non stroker

People have built 500 bhp street motors from 351 cubic inch Clevelands since the seventies. Back then it was solid flat tappet cams, duration at 0.050" was about 246 intake/256 exhaust and about 0.600" lift on both lobes, these numbers would vary from cam grinder to cam grinder, but this gives you a ball park idea. Ported 4V closed chamber heads, Holley Strip Dominator or Blue Thunder intake manifold. Breakerless distributor. 750 to 850 Holley carb. 1 7/8" - 2" headers. In general, whatever had the biggest primaries and would fit in the chassis. Powerband of 3000 to 7000 rpm. Torque peaked around 420 ft/lbs and was still around 380 ft/lbs at 7000 rpm, which is the magic number to get you 500 bhp at 7000 rpm. The secret to cleanly carbureting at low rpm was simply having the carb & igntion dialed in properly. Calling ths motor streetable needs to be qualified, because one man's streetable is not another man's streetable. This motor needs a manual transmission and some fairly low gearing.

This is "big block" horsepower, from a 351! Its a bitchen motor, the Cleveland made small block Chevy guys pee their pants in fear and cry fowl.

I would advise if you plan to open road race a motor like this to buy a heavy duty block & protect your investment, using the thin wall production block is like playing dice, you never know when you'll roll snake eyes, but eventually you will. Bush all 16 lifter bores & set the clearances between lifter & bore at 0.0007" (that's not a misprint), install the high pressure relief spring in the oil pump & use a heavy duty oil filter (Fram HP1) and a good baffled, windage tray & scraper oil pan. You can also install the restrictors to the cam bearings, but don't restrict oil to the left side lifters, you solved the oil control problem with the bushings, oil will now flow to the main bearings, you need to let oil flow to the top end because the springs are cooled by oil. Finally, you'll need to run external drain-back lines from the heads or valve covers to the oil pan to prevent the pan from going dry, especially in a long race like a silver state. To get oil to drain you need to open up passages between the heads and the lifter valley, and connect your crankcase evacuation system to the fuel pump block off plate, this way air flows through the motor the same direction you want the oil to flow, not against the oil. Make sure you dynamically balance your reciprocating assembly. Rock and Roll!

The racers who made the Cleveland famous all had their hands on good blocks, not production blocks. The heads will make more bhp than the block was designed to tolerate. Drag racers get away with subjecting the block to a lot more power without failure, road racing is tougher on motors. Drag racers only travel 1/4 mile at a time. Their cars cover less than 100 miles in a season.

Stroking simply allows you to make the same kind of power at a lower rpm, which makes the motor more durable, and more drivable.

Sounds like your combo is working for you, what are you looking for, more bhp?

cowboy from hell

It's an engine, it's not a motor. What's wrong with you guys?
Sounds like a pretty decent ENGINE to me.

Who the hell are you listening to? Maybe them Gucci loafer geeks?
Maybe the Bite My Weenie jerks? Screw the bunch of them.

Koool 'new' Avatar George. Many thx agin for all your 351C 4V 'old way' info. - You didnt mention comp. ratio....They would have run pop-up pistons i guess with about 11.5/12.00 then? Can the 'quench' heads really get away with that much comp?...not on pump gas? - I am taking your sage advice and will go with a stroker-kit soon. Will run with my old 48IDA's and open up the 180's to 3" collectors as adviced by you. - Would my presnt Hyd.(Sig Erson)cam at 228* @ .05 + 5.45" lift (you said; less duration and more lift) work OK? - Iam not looking to rev too high as u can see...I enjoy the off-idle grunt alot....i know you've been thru all this before, sorry....Cheers,

quote:

Originally posted by Tai Krige:
...You didnt mention comp. ratio....They would have run pop-up pistons i guess with about 11.5/12.00 then...

I always ran fordged flat top pistons, with the block "zero decked", which is good for 10.0:1 compression ratio with '71 heads, 10.4:1 with '70 heads, more compression if the block is bored.

Thats all you need with pump gas here in the states, even back in the seventies.

Yes lots of guys ran pop-ups and higher compression. I've always been "mister conservative", I learned to work on motors from old guys, it rubbed off on me.

In regards to cams, I learned as a young man that off the shelf cams only work for your combo if your combo is close to the combo the manufacturer designed the cam for. Custom ground cams, ground by somebody who knows the motor very well, will work better 100% of the time. That's the best advice I can give you.

cowboy from hell

quote:

Originally posted by PanteraDoug:
...It's an engine, it's not a motor...

Engines convert heat energy into mechanical energy. Motors impart motion. An automobile engine does both of those things.

Afterall, they are called "motor vehicles".

cowboy from hell

Thanks George & Doug,
Just want to keep up with the new vehicals the car builders are putting on the street without messing with a combo that work's already.
I get a certain joy when I take this 35 year old supercar and blow the doors off some clown that's laid out excessive cash on some car that they never even wrenched on.
Ive been Hot Rodding eversince I can remember,at around 5 and the old man had me stripping paint with him on a 32 ford roadster and haven't stopped since. like many I do the Majority of the work myself and let the Pantera do the talking.
Here's the gig! I want the best all around function from the Pantera. ,all the compression I can squeeze out of 4V Iron heads on Pump gas,a rowdy cam that is still driveable just to let all know a Pantera Just Showed up,want to still be able to run all out and still drive it home. Keep the grill over the Engine stock.Do you have any number's or ID's for the heads?

If you want to build a stock displacement motor the only thing I would change from my previous description would be to use a solid lifter roller cam. Custom ground by MME Racing.

Let MME tell you how much compression your motor can use, Cleveland heads cannot be identified until they are removed from the motor, 1970 heads have a casting number of D0AE, 1971 heads have a casting number of D1AE.The remaining heads are open chamber heads.

The casting number is located on the bottom of an itake port, which is why it can only be seen with the head removed from the block. The thing is, once you have the head off the block & turned upside down to read the casting number, you are staring at the combustion chamber, you don't need the casting number to tell you which combustion chamber it has, DOH! see pic

cowboy from hell

Should not be too hard to do. Roller cam of about 240/250 duration at .050. Holley strip dominator intake. 850 CFM carb. Mind train exhaust (NO GTS mufflers). 11:1 compression. Pocket porting of the heads. Roller rockers. This should get you an easy 500 hp at somewhere between 6000 and 7000 rpm.

Here's a little info about Cleveland compression ratios I put together long ago: