Originally Posted by B3422W5
Originally Posted by AndyF
Thinner rings and a vacuum pump can add 50 hp to a race engine but the rest of the engine needs to be able to support another 50 hp. If you have good heads, the right cam, a good carb, etc. then sure, you should pickup some power.

If this is a dedicated race car then you might want to think about adding compression at the same time. For bracket racers I always recommend picking the CR according to the fuel that you can most easily find in your area. Usually 112 is available also everywhere so if that is the case for you then match your compression ratio to what works well with 112 and the engine should be happy for a long time.


Nowhere that I have lived or raced have I ever seen 112 available except at a track, or in pails/ drums from a fuel vendor.
On the other hand, 110 is readily available at the pump at a number of gas stations. Seen it available at the pump pretty commonly most everywhere.
112. Never.






Thank for all your input guys!

110 is what we normally run. It is readily available at the pump in our area.

My father in law would really like to get into the 5's , but he ties my hands. I can't lighten the car at all. No rear gear change, no aftermarket block. We have been making north of 700 hp for 10 or 11 years on an oem block with no failures. I'm afraid that will change if i increase stroke or rpm range. So I am just trying to maximize what we got, within the rpm range we are currently running. I talked to him last night about a 4.5 bore block. He feels that he is too old to get his money's worth out of it.