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.