Carl, my only concern with your combo is 3900lb car, close ratio (2.32) 4 speed, 3.5 rear and 29" tires. Might be hard to get it off the line? Easiest and cheapest thing to change are the tire height(lower), second ,rear gear, 3.70 or more if you keep the tire height, (although bearing in mind your highway driving) With that current setup you will be doing about 2400 @ 60mph, which is fine on highway, but it's the initial takeoff in 1st gear (2.32) which might need some revs to get off the line and maybe chirp the tires pulling a heavy car? Others might have some thoughts on this?