For what its worth my old Kougar has a GMS 47 in it with the
Tower tuned muffler. It swings an APC 10 X 7 at around 13800
rpm and hauls the old Kougar around with authority.

The only other plane as fast in our club is a Direct Connection
F-20 with a YS45 on it. And I can usually keep up with him.

Here is a pic of mine. Its not too pretty but flies good.

Mike Hammer