Hello everyone - My son-in-law and I built a race car, 1972 chevelle, this year and run it at our local saturday night track. We have a 350 engine with 308 heads currently and are having problems with what I believe is too much compression. We have a set of 400 heads laying around and I would like to know what to expect in the performance department if we install 400 heads on a 350 block.