It only took a week for the engine shop to bring me my engine back.
This time everything went as I expected. The take off was entirely uneventful except for the vastly improved performance. With the O235, the 64kt Vx produced an absurdly nose high attitude, that had to be slowly lowered to achieve the 78kt Vy. Now at the same attitude, it just accelerates right to Vy and climbs at 1500+fpm.
It did not take long to convince me that the O320 is the engine that should have been in the plane from the day it was built. I can cruise at 105kts while consuming less than 5gph (better than I could do with the O235). I can effortlessly climb to10,000 ft to take advantage of tailwinds or higher TAS at lower fuel burns. For short trips I can go almost 140kts if I can tolerate almost 12gph. A more reasonable cruise is 7500ft 130kts, 7.5 gph
I have not completed flight testing to compile performance data on climb, cruise, and fuel consumption, but I have added a manifold pressure gauge so I can document actual power settings at various altitudes.
I can only say that every time I fly it, I walk away thinking what a great machine it is. I get to fly an awful lot of varied aircraft, and few make me feel that way about them. Some of my other all time favorites are the Twin Commanche, Cheyenne 400 and the J-3 Cub and Robinson R22, so the AA1 is in good company.
Its been almost 10 years since the conversion, and all of the above still applies. I have changed little in that time, probably the most significant change was to add a KLN90B approach approved GPS. My son that learned to fly in this airplane now flies a Hawker 900XP for a living, and he still delights in flying the Grumman, he walks away from it with a big grin every time.