You'd be better off with a t2 to be honest dude, mirage manifolds would prevent you from bulkhead cutting, you'd need headwork an atleast a 4pin diff, aswell as the carb, fuel pump, extra fuel lines an fuel reg. You'd probably do it for under a grand an get you around 80bhp.
You'd be very limited to boost thou, anymore then 8-9 psi an I'd say you'd be in gearbox wrecking territory.
Be cheaper to buy a 1275, big valve head an hot cam I'd say. Probably be better reliability an economy too...