What is the best timing for it? That can make a huge difference all by itself. New pipes and headers will have to wait a bit, but are anticipated. Camshaft is a huge item too but a lot bigger job than setting timing. And, besides, I'm not sure acceleration an elderly fellow should be allowed. A 3:07 rear end isn't too bad especially out here where there is a lot of cruising and not a lot of stop and go. I think a 3:54 is a nice compromise.