i am currently building my first small block motor! im building a 350 chevy for an airboat.. what im wondering which heads would produce the most horce power?? 305 heads?? 327heads?? or 350heads??and if i use the 305heads would i need to get bigger valves??? and if so what kind should i get? i appreciate all the help n will be signing in every day till i get some feed back!thank you have a good day. brandon