Well you have lots of technical info, it seems you have a philosophical question... a poker game, do I keep what I got, raise the stakes, or fold. After the last election I would absolutely put what I got together and ride. For every one of you guys with questions... there's two out there wishing they had your problems! The only way to get 20 MPG to me would be dropping in the entire Mag drivetrain out of a Dakota. If all your stuff was small block I would say the same thing... selling/trading/buying/rebuilding is all time consuming but most of all ...INEFFICIENT. I could make a flathead V8 efficient by drowning it in all new-tech parts and a 6-speed etc. Get out there and drive before we can't anymore.