Been gathering up parts to rebuild the engine in a 89 5spd IROC G92 optioned car. Going to keep it all stock numbers matching(am adding a 400 crank). Anybody ported the stock manifolds and seen any difference in performance. Not looking to make the car a killer but the hot rodder in me is still alive. Thanks

 

I doubt you'll see any noticable gains. The manifolds are very poorly designed. If you have the time, it won't hurt, but again, I doubt you'd see any gain if you did a back to back dyno pull.

 

zero

 

Not suprised. At least they have 2.5 outlets. thanks for the replys

 

I've been told that cars don't have anything like matching numbers anymore just the casting numbers. All cars with the same motor have the same number.

 

There will be a partial VIN on the block that matches the car.

 

I was just at Dyno Don's shop. He told me and I check for myself on the 3 or 4 motors he has on stands and believe me the only numbers on the blocks were the casting numbers from the mold and the engine size in liters. He showed me the location where the VIN used to be stamped and the are completely blank. Believe it or not.