FWIW, I built the 'glass fuselage version in the mid 70's...

How much does the .55AX w/ the Jett muffler weigh? I had a K&B .61 w/pump on mine (stock muffler ) and it balanced just about on the aft limit, so we added a little lead to the nose.

Don't want to sound critical, but I'm just thinking (especially after reading the Quick Fly thread ) that with some of these older airplanes with long tail moments, one might just as well use a .60-.61 rather than have to add lead to make up for the wt. "saved" by using a lighter engine.

If the tail feathers are kept as light as possable, it might be o.k. with the .55AX though? (just putting this out there for your consideration )