sbc buildup
 

Ok guys i need some help here. I have a 400 sbc in my chevelle it's putting out around 550 hp. But in the past few weeks it has developed a knock. I have checked everything out and it seems to be coming from the bottom end. So i guess it's time for a rebuild, so here is my question. Should i build a 400 or should i go 383? My 400 is a 2 bolt block. I just bought a set of 200 etec heads and have had them on there for only about 3 months so i will be reusing these. My plans are an engine with about the same hp as what i have now N/A, and then adding a power adder of some sort. What do you guys think and why? Thanks for your help.

Brad

I would say keep the 400, the long stroke over the 383 will develop more low end torque that will help move your chevelle(bit heavier than a camaro/nova). I would say rebuild it as a low compression blower motor and add a D1SC to make a motor putting out 800+ horsepower that is pump gas compatible.

EDIT: 383s and 400s have the same stroke, I must have been thinking of a 377. Either way I still say the 400 is a better choice.

I agree the 400 is a better choice. If you were to go with a 383 remember that
the block will be bored making the walls thinner. Were the 400 is a bit more meaty and will take the presure from a Procharger much easier. Plus you already have it.

Have your 400 block sonic checked so you know what you're dealing with.

400
 

I agree with above and definitely the block checked first. You can alway have the machine shop put a 4 bolt splayed mains on it. I would also go with a 5.7 rod since you are having to change pistons as it will cut down on the rod angluation.

Ok thanks guys, i plan to pull the engine this weekend and drop in a temp. 350 so i can take my time and build the 400 once the right way. I will be going forged all the way through. I'm not taking any chances on this build, it will be putting out to much power to go cheap. Thanks again

Brad