I'm running 24v tappets on my 12v cam.
I have my old tappets that my machinist resurfaced for me just sitting around.
Tappets are fairly inexpensive , why not use new ones , in any case the 12 , 24 valve and CR tappets are the same height, but you can not run the small 12 valve tappets on any good perfromance grind ,
the 24 valve cam is a far better cam then a 12 valve
How's the 24v better? Isn't there only a little difference in the exhaust lobes?