I am planning on building a 65" warbird and was trying to decide between the tower .75 and the gms .76. It sound like both engines offer about the same power and are both reliable from what people are saying. I own both gms and tower .46 engines and have been happy with both. So I guess my question is which is better abc or ringed style engines?

When you have to rebuild a ringed engine do you only have to replace the ring or is it also necessary to chance the cylinder sleeve? I heard that the break in period for a ringed engine is more difficult and that they are more easily damaged from running to lean. Anyways would like to tap into some experience here.