Magnum rocker arms..any problems??

If you just want the 1.6 ratio, just get 1.6 rockers for LA heads. Hughes Engines has shaft mounted rockers for Magnum heads. It's actually 4 shafts per head, each with 2 rockers.

I have Magnum heads (EQ, not stock) with a cam that has just over .600 (not including the loss for pushrod angle) lift with stock 5/16" size studs. If I did it over, I wouldn't use Magnum heads. Haven't had any problems, it's just that there are better out there for about the same price. My Magnum heads can't handle a cam that will allow them to live up to their full flow potential due to the weakness of the stud mounts, at least not comfortably. With the Hughes stud mounted magnum rockers, they probably could, but that would be another $400+ that could be spent on porting, springs, etc on a set of LA heads.