Are we talking solid street roller or hyd.? The only time I use LA heads on a magnum block is if we're running TD rockers because they can oil either way. The comp's are meant to oil from the head.
I have the RHS head in Magnum version and you can use Hughes 1.65 rockers coupled with hyd. roller you can really make some steam.
Or you can use edelbrocks magnum head and stud mount works ok just can't get real aggressive with the cam unless you go to a better rocker (td) which are costly.
The retrofit hyd. rollers are ok, but you need to grind clearance for them in the valley. So no real easy answer I guess sorry!
Brian