my datsun gx cam is damaged. what can i do ?

Can i polish them all?

Were can i buy a new one?

if it's an a12 cam, there are a few nos items out there, but if it's an a14 cam, you need to get a regrind

Right. Get it re-ground. Any camshaft company should be able to restore it to the original A12GX specifications.

Don't try to re-use it. It will simply damage the new lifters. Always use new lifters with a new (or rebuilt) camshaft and follow the mandatory camshaft break-in procedure.

I've been told that all Aseries cams are interchangable. True?, but did the larger motors had different profile cam?

Different cam profiles interchangeable...

However, the camshaft also drives the oil pump and distributor. Camshafts are physically different starting with 1974 model year engines, because the newer engines have the distributor in a different location.

See Datsun 1200 Encyclopedia - Camshaft

Datsun A10 & 1200 engines, with the distributor at the front, use a single drive gear to drive both the oil pump as well as the distributor.

From 1974 ALL Datsun A series engines used a second drive gear as the distributor was now re-located back where the earlier fuel pump once was.

You can use the later cam in the earlier block as long as you block off the fuel pump mounting & run a different pump [electric?], but if you wish to use the distributor in a later model engine, then the earlier cam will not work as there is no drive gear for the distributor.

Late cam [two gears] = can be used in all engines. [conditions apply for early blocks]
Early cam [one gear] = Can be used only in early engines, if you want to use a standard type distributor ignition system.

this egine had no fule pump, it was electric. i think im gonna stay that way.

so i can use a 120y cam in the earlyer block and use one electric pump.
that is a good idea.

thanks