Well, I know many won't like this news, but mine, when new with a ZDZ 40 just did NOT have the punch I wanted....I love the tumble-bug airshow type stuff the Pitts excels at, and the 40 wouldn't give me recovery power.

Then - After a hefty investment - I bolted on the Taurus T-52. And almost immediately had to reinforce the firewall. But it sure turned this beauty into a beast.....

I've owned and run OS 1.6 on Caps, etc. Wonderful with a Master Airscrew 18 x 8, but on the 14 lb Pitts, it ain't gonna make it. At least not "fun"....IMHO, of course.