I just looked they all seem to be the same size chamber. Commandos are the smallest as 60cc and have great potential when ported.
Indy makes 2 heads. Oval port for small cube motors and rectangular for strokers. So if the indys are what you want you can go with the oval port and matching intake.
I though there were a few heads that were in the 58cc range but I dont see any listed. You can all ways mill a set of heads to bring the compression up.
