Engine is usually the last choice, or a later one anyway. What are you looking to build? Something light or something fast? I am building a modified Long EZ that will do about 240 MPH. Have flown the prototype a lot. Its awsome. I will put an IO-390X in it. IO-360 in the other one and it flys very fast. Lots of fun.

There are a lot of kits, are you trying to do that or build from plans or scratch? Mine is all plans build, which means I make all the parts. Kits are easier because you don't have to fabricate everything.

What are you interested in?