318 Crank

[skymynx]

I'm in the process of restoring my 318. I'm throwing in some Federal Mogul forged pistons and eagle rods. I've been reading up on the limits of the parts I'm getting and it seems to be safe to stay in the 500 horsepower range. I plan on only running about 400 on this motor as it belongs to the girlfriend and don't want her running around with two much power. What are the limits though of the factory crankshaft?

 

[19mopar65]

what year 318 or do you know if the crank is cast or steel?

 

[skymynx]

its from a 1972 charger. I'm not sure on what the crank is, as I won't be pulling the motor till I put it away for the winter.

 

[Meep-Meep]

To immediately address your question I think it's impossible to determine how much HP the crank will take unless you've run over a few, but 400 HP is not that exotic of a number so probably work out fine. To get that HP out of a 318 you are probably looking at 6-6500 RPM shift points, fairly radical 108-110 deg cam, free flowing heads and high compression.

Just my opinion, but I'd build a solid 300 HP engine that peaks around 5500 RPM with good mid range torque - kind of like a stock 340 - and use 3.55 gears. This can be done with stock parts and cast higher compression replacement pistons (KB's) and not a lot of $$$$$ Or do a similar build on a 360 tractor motor. Hmmm, not sure of the main size difference, but how about popping in a 360 crank and rods into the 318 for a cheap stroker?

 

[skymynx]

We are looking to supercharge it with a paxton setup. Will be rebuilding the motor sometime next year once we get into a house. We are currently house shopping, and I don't want to transfer the car with the motor out. Just not worth the hassle.