Hi ALL, I have been flying for 22yrs and I am only 28. I live her on the beautiful island of Guam where their is flying weather all year round. I was an Apache crew chief in the Army, so you are right about specifications in that aspect, but in this hobby in my experience. I have found that the engines a manufacturer recommendes flies the plane, but thats it. Some of us pilots need a little more. As for the G.P. Pitts I will be putting a Brisson 3.2 in it. it is lighter then the G45 and the US 41, but in turn has more power. I believe this will give me almost unlimited vertical. In my opinion it is better to have more power then not enough. You don't have to stay in specs all your life, have a little fun. Its ok to bend the rules now and then as long as know one gets hurt. As for the 4.6 WOOOOW. That is over kill. Hay, good luck anyway. I know I wouldnt mind watching it fly.
Best regards to all.
Duayne