g3 to ca33 conversion?

[eatthis]

i have a g3 (jg) and finally found a metal receiver for it, problem is its a ca33 and i didnt know they were different lol.
apart from the lower receiver and stock (and mags) is there anything else i need to swap?
also where can i find the bits? google hates me and i dont mind 2nd hand parts or even a knackered ca33 i could cannibalise