Change in plans... Anybody used a "retro-fit" roller cam in a Magnum?
Make sure to check the piston to valve clearance while you have the heads off. I have .534 lift on the exhaust valves (regrind cam around 150$ or so after shipping), and I believe they might have hit the pistons because all the exhaust valves leaked when I replaced the valve springs with Hughes 1110 springs. They for sure weren’t leaking that bad when I put the engine back together. I don’t have any issues with the retainer to guide clearance with the 1110 springs and matching retainers. I’m running mr gasket .28 head gaskets, and the Hughes mech. fuel pump extension with it too and I haven’t had a problem with them after many hard miles.
I’m running the stock lifters with probably over 150k on them (junkyard engine). I checked them out before putting them back in the engine though. I’ve ran it past 5k rpm quite a few times and had it in traffic a buncha times. Ive heard them make noise during cold starts sometimes, but the engine runs strong to this day. But for sure, if you have the money I’d replace them with maybe some sealed power units. With advance auto discounts you can get them for probably less than 160$.