Sounds like a lot of hassle to be honest. Guessing it's a racing puma spec engine if it's up to 150?? You'll need different engine mounts, the gearbox is different-ib5 as opposed to mtx75 i think (not sure how this differs with the cables/rods but might mean you need different driveshafts) pumas also run the variable cam timing and I'm assuming you'd have to run it on a racing puma ecu and loom. Could put any engine you want in for that much messing about. You can get an st170 lump for less than a grand and I'd imagine they just drop straight in.