318 Head Opinions
I like the Magnum heads for certain build up as well. The stock head off a "LA" isn't to bad and easy to up grade. It becomes a catch 22 at this point. Sometimes it is worse when someone allready has a cam with alot of lift that the change to a Magnum hed can not be done as cheaply as off the J-yard car onto his engine without added expense.
The 302 is a nice head that ports out very well. If you all ready had a set or acquire a set cheaply, then it could pay off easy to port them rather than going toa Magnum head and added expense of acco. parts of the swap.
The price of porting a set or 302's vs the Magnum swap and possible cam change is a pesonal call at this point. If the 302 is in good shape, the porting price is about the same as the Magnum head/cam swap.
I agree on the cracking. If it ran lean to long or hot to long, cracks will be there. The are also not the end all.