The only reason I would ever consider a destroked motor would be to compete in a cubic inch limited class, a class were you were required to weigh x lbs per ci, or simply because that was the parts I had. The reason NASCAR runs big bore short stroke motors is because they can not run larger than 358 ci. By running a larger bore they are able to stuff larger valves into the heads and make them breathe better, then they have to shorten the stroke just to stay in the ci limit. If they could run larger motors, I guarantee they would increase the stroke and change the gear ratio's to keep the rpms down lower and increase reliability. Stuff breaks a whole lot sooner at 8,000/8,500/9,000 rpms than it would at 6,000-7,000 rpms. I am building a 377 sb for my project car as well, not because it will be faster than a 454 sb, but because when I started the project I had a GM steel 350 crank and did not have the funds for a $2,000.00 stroker crank so that is what I am going to use.

 

i know that aemerican speed build the 377ci engine for the ultima because the gearbox used (porsche tansaxle) is only rated to about 600-650lbs ft in the strongest form! also the higher rpm complment the light weight of the car!

but its horses for causes and engines for cars so it depends on what you are doing/looking for!

Chris.

David, yeah i forgot about them! lol guess it most be a combination of things then! light rotating mass and very good balancing. i know the honda and BMW engines are hand built, how about the Audi unit???

 

I think everyone here has this phiosophy down very well for once! LS1Tech is getting much better!

Destroking an engine is almost aways a result of displacement limits and trying to keep all the bore possible to run the better heads with larger valves and ports. In this way it is right and makes perfect sense on an all out displacement limited racing engine.

On a street car it just resuts in less power and reliabiity than the larger sized engines can be run with no penalty. Otherwise it makes little sense usually.

 

I remember seeing a quote from a noted engine builder, I forget who, who when questioned about rod length said they didn't care it didn't make much difference.

I actually had a 3.27 crank out of a 4.8 in a box for a while, and was going to build a 6.0 iron block 4.030 over with a 3.27 crank. In the end I didn't think that it was worth it.

 

I'm looking to do the exact same thing for the GTM. I'm hoping to get started on it in about 6 months

I may end up just putting something fairly mild. It's gonna be friggin quick anyway, and my wallet is already hurting in anticipation