A good tune-up (spark plug wires, spark plugs, air filters, change all the fluids, dizzy cap), bump the timing a little bit. search for the sixlitre tune-up. cold air intake, headers, new Y-pipe, whole new exhaust, edelbrock intake, some gt40 heads.
all depends on how mechanically challenged you are and how big is your bank?
Sealed......Otherwise you'll be pulling in so much radiator, engine, A/C, P/S and exhaust heat that any insulating you do afterwards probably won't result in the intake charge being any cooler than if you'd left the factory system in place. In fact, you may find that the excersize was for nothing.