stock 5.2 Magnum valve springs MAX LIFT

The consensus my research indicated was .520 before machine work to the guides.

Agree on changing springs.
Stock magnum springs are done at 5000 rpm. My mag has the 1110 springs also Hughes retainers 512 lift cam and .020 guide clearance. I did recently read that Hughes has retainers to solve this clearance problem if you cam is .533 lift you better make you have valve/piston clearance