318 2 barrel? Put a 600 4 barrel on with a adapter or a intake if you wish. Keep the exhaust manifolds and add a dual exhaust and have someone like Halifaxhops set you up with a performance distributor advance curve. The stock convertor will be fine and depending on what rear end you have, a gear change makes it peppier. (3.23-3.55 depending on rear tire size) Any other modifications to a stock low compression teen are either a waste of time or money unless (unless) you want to build the engine from the ground up.