You're gonna need the mounts to swap over the new engine,computer and all the wiring to get it right. Also a LS headers setup will be needed to fit in the engine bay with the newer engine. Not sure if you're gonna carb it but the fuel tank will need a fuel sending unit if you don't use a efi kit. There's a red 72 somewhere around here that has a similar setup....:secret:
It's a lot of work. Figure $1000-$2000 for extra install costs over and above engine cost ( Brackets, Headers, Exhaust, Fuel Delivery, Wiring and programming). Hood clearance may be an issue. Can be solved with more money.