I am 16 years old and have just broke in a sbc that i built a few weeks ago, i was wondering if any of you guys could tell me how much hp i have or give me a good estimate. Here are the specs: A 4-bolt main block, steel crank, bord .60 over, stock type pistons, lunati cam with 292 duration and 480 lift, stock heads, edelbrock dual plane intake, holley 670 street avenger 4-bbl, and a set of cheapie heddman headers. Thanks for replies in advance
you might want to tell us what the motor came from if the parts are "stock" or "stock style" because its going to be different stuff ina 67 vett then a 75 truck
300 at the flywheel, maybe. The key is to get it to breath, the more air and fuel you can efficiently move through the motor, the more HP you can make. With "stock type pistons" (I assume they are at least flat tops) and "stock heads" you will be somewhat limited.
the motor originally came out of a 1970 C-60 dump truck, its an industrial motor with 4-bolt mains and a forged steel crank, and it has the stock flat top pistons for a .60 over bore, currently the motor is sitting in a 1972 C-10 pickup. Its powering a th-350 tranny, which is turning a set of 3.73 rear gears.
And of course cubic inches. If it is a strong running 350 cu in. My guess is around 200-ish. at the rear wheel. There are a lot of variables though. Compression ratio,optimum fuel,state of tune,wear. Tourque peak,and actual maximum HP are hard to just 'guess' I know there are a lot of 4cyl.'tuner' cars with over 500hp. Sparky
I wasn't aware that headman made cheapie headers. Doesn't matter how muny ponies ya got hows it feel in the seat of your pants? Unless you're racin professionaly as long as it gives you wood when you stab the loud peddle that's all that matters. Oh yea don't tell the Doc I said that.
From your description it sounds like millions of other small blocks that put out anywhere from 250=300 hp. That's what similar factory small blocks were rated at. Yours could be a little more or a little less. Like everyone has said, it doesn't matter as long as it runs well and gives you a smile when you push down on the throttle. If it was assembled properly and clean, the tolerances were within factory specs, you should have a powerplant that will give you a few years of reliable fun if you maintain it. If, in the future, you have a desire for more it's available, just get out your wallet. Frank
Ran this through Desktop Dyno using some assumptions about valve size and CR, too many assumptions actually. What it spit out was peak HP of 268 at 4500 rpm and peak torque of 343 at 3500 rpm. It was pretty much done for at 4500 but had nice flat curves up to that point.
The problem is... you've stuck a big cam in a stock motor. The steel crank isn't going to give you any more horsepower... nor is the 4 bolt main block... the .060 overbore isn't going to give you much more than a .030 overbore, or a stock motor... the compression is probably in the high 8:1 range if you used stock type pistons, and a thick head gasket, and could be worse if you have heads with a large combustion chamber... Sam.
that's the only kind I've ever got from them... Yeah, a stock 350 with a lumpy cam is a bit mismatched. Some head cleanup porting would probably be a big help, and put it over 300 hp. btw, the 250-300 hp numbers are at the flywheel, and Sparky's 200 hp number is at the wheels, they mean the same thing though. there's a lot of power that doesn't make it to the ground in any car.
thats virtually the same cam as the comp 280...it has a 230 actual duration @.050 and 480 lift....i believe it is Fat Hack's favorite grind
That is hacks fav its what i have in my 305.. and im lucky is i have 160 at the wheels but mines all orig and i dont have any cool stickers to make my car faster like the import crowd does.
Thanks for the numbers guys. The truck has really good seat of the pants power and with the 3.73 gears it has a good kick to it. Thanks for all the replies and constructive critisism
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