400 (451) in '68 valaint????

You can leave the T bars, unless you go factory manifolds and stock iron heads. I would suggest loosing both. EIther a set of Edelbrocks or the Indy SREZs will be a better choice, and help the weight thing. The easiest deal is a motor plate, and a cable shifter, with a good set of under chassis headers. The factory mounts are the best for a street car. You'll need to upgrade the cooling system, and add frame connectors..Then go have a ball.