Prepare for the magnum heads to be cracked and have pitted and sunk exhaust valve seats. Something I didn’t realize myself before my magnum swap and ended up costing me a lot more than I thought I would spend.
True but they still run and run good. My take is do the swap with lapped velves and new seals and the Hughes spring kit.
Later upgrade cylinder heads.
LA's are all okd and need seat and guide work by now also so in my mind that's a wash between LA and magnum engines.