hey guys im still gathering info on this but is it possible to use this? or are the larger motors have larger cams??

YES, if your A12 is a 1974 or newer.

A12 option camshaft was the largest factory cam, larger than any A14 or A15 cam.

The A12A block I think is the same however the A12 block has
the fuel pump or oil pump in a different location than the A14/15

hey wubbits long time no hear. welcome back.

Yes, A12 1970-1973 is different. A12 from late 1973 to 1994 uses same camshaft as A14.

you can run the newer cam with the older engine if you use an electric fuel pump. Because the fuel pump lobe doesn't line up with the older engines.

As usual, David is right, the later cam [1974 onward, any A series version] will work in the early [front distributor] block if the standard fuel pump position is blocked off.

The reverse will not work however. [early cam in later engine]

All 1974 & later A series cams are directly interchangeable but the timing specs vary a little bit depending on engine model & year model.