Bought a new/old stock AE camshaft to suit XR RS etc from '80 on thinking they were all the same.

However I have just tried fitting it and it does not go all the way in.

Upon further inspection the pulley end has a notch cut into it not a woodruff key thing sticking out which would suit my exisitng pulley.

So what the f have I actually bought and can I just replace the pulley, maybe get a vernier this time instead of replacing the cam?