Anything can be done if you have the time and money. But this is not a swap
worth doing unless you're just doing it for fun. If you're determined to change the
engine find one for the same year of GTP. Everything will fit and it will only cost a
small fortune in labor instead of a large one. In terms of money the car is really
not worth it. I would add a couple of units of Bars Leak to the cooling system
which may take care of whatever gaskets are leaking and see you through to the
end of the car's lifespan. Did that to my car years ago and it still runs fine and I
haven't replaced anything. Cheapest "fix" ever and totally GM approved
regardless of what your mechanic might tell you. Save your money for buying
your next car.