Small Block HP - How Much?

[Richard Hudgins]

Originally posted by scottj
Fred,
Not necessarily a ye wise man but, if you want to go square with a Dart block why not a 447 (4.155 x 4.125)? I stay at 434cid (4" stroke) since efficiency and reliability are already compromised with the 434 combination. When over 400cid, the 4.030 bore isn't really an option by my way of thinking, for efficiency reasons.
Scott

Hi folks,

Another option is to go quite a bit oversquare such as 4.155 x 3.5 for a resulting 380ci. This will keep piston speed at 8000 in the 4600 fpm range. This speed is quite liveable and rod lenghts are very good, etc.

With proper heads and cam profiles, you could have a motor that would give you an effective powerband from 3200>7500 that would live forever. (A subjective term)

In addition, the combustion chamber area ratio would quite good and flame path and timing would allow a fairly high CR that could run on pump gas.

I would guess that 550 hp and 500 torque would be quite realistic with these sort of numbers.

Maybe Andy D. (The Butcher) could run some numbers on his trusty desktop dyno.

After all, current F1 motors are 3.8 x 1.85 10 cylinders for 3.5 liters and they produce 800 hp at 18,000. 5500 fpm piston speed with seriously exotic materials. Power band from 8000 to 18,000 is really cool.