factory magnum head replacement options

Please expand on that statement sir-was looking to try a set on a roller 318 instead of using the 302/741 roller heads.
When the eq heads moved overseas to China (from Australia) the quality went away fast. I actually don’t even think they are even the same casting but I could be wrong on that. There are plenty of threads here showing how bad these are ootb, just do a search. That’s not to say they can’t be made to work, but the cost for the machine work often outweighs just buying a better set of heads to begin with, and on top of that you have to find a machinist willing to grind on cast iron.