Expert: Dan Liddy - 3/25/2004

Question
I am considering having my 350 bored out to 383. The 350 just does not have enough power for me so i figured id rather stay legal and get more cubes than bolt on a supercharger. The engine runs great how it is, and i know the saying, if its not broke dont fix it, but if i get it professionally done, will i see improvements in performance? or will it be a waste of money. I have already bolted on the aftermarket parts: edelbrock carb and intake, cam and headers. So my question is, if money is not really a problem, would it be worth it performance wise to stroke my 350 to a 383?  

Answer
Hi Erik:

OK  First, are you going to bore it, or stroke it? They are two different things and the results will be different as well. However , either one will increase your displacement which will have a direct effect on power output. Going from a 350 to a 383 is a 9% increase in displacement, and will produce a 9% increase in power.

I think if it were my project, and money wern't an object, I'l bore it AND stroke it to a 400 ci. It will cost a few hundred more, but the gain will be 14%  instead of the 9%.  

Another thought, what is the compression ratio ?   can you increase it and still run pump gas ? If that's the case, machine the heads to increase compression, but calculate your ratio before doing so or you might get it so high that it will detonate on pump gas, then you're stuck with race fuel that's $4.00 a gallon. Anything over about 10:1 is hard to handle on street fuel.

If you don't know how to calculate a compression ratio, you need to study the subject more. HP Books publishes a book about 'blueprinting' that will explain it all to you in easy to understand terms. If you can't find it at a local book store, they can order it for you, I think it's about $15.00 and well worth the cost.

Whatever you do, avoid the big blocks (427,454 etc. ) they're BAD on gas consumption, and it ain't getting any cheaper.

Good luck with your efforts, hope I was a help !

Dan Liddy
Sarasota, Florida