Just wondering if anyone has ever tried this? I have a set of factory mag heads I'm working over for claimer racing that require production castings, and was looking for a little more flow. At first glance they seem to be very close in length if not the same and look like they might be a cheap upgrade for more flow. Stem size is the same so no guide work, and the only difference I see is the the lock grooves. I already have a full set of hemi valves so basically all I'm out will be the valve job. Since the hemi valve is only slightly larger at 2.00" vs the stock magnum is 1.92" its not a huge gain but would surely be worth a couple CFM.
TIA

You lose by my calculation between 0.060 and 0.080 installed height. Depending on your lift rules, you may have trouble finding a valve spring strong enough that'll fit in that small distance without coil bind.

However, Comp Cams is now recommending running springs to the minimum allowable height whenever possible as it damps out spring harmonics. At least that's what I remember.

Hughes 1110 springs is where I'd be looking.

Another concern is valve head shape. The Hemi head may require a different head shape than a wedge, like tulip instead of nail head, something like that. The wrong head shape may negate any flow increase from diameter increase. Or not.

R.