Question- I am switching over the 90# springs from the old heads to the new ones. My question is that I have ZZP stainless valves in the old one as well. Should I switch those over? I’m not sure how much of a difference if any the stainless valves would have over stock? Thanks
The stainless valves really won't make any difference. If they are oversized, they might help a very small amount. I would probably swap them, since you're taking the springs off anyways. But, it really won't make any difference either way.
2001 GTP Drag Car - XPZ, Tischler heads, Upsidedown M90 IC'd, e85, Gen V, 2.3 w/ 5%OD
2005 F350 6.0 - studded, deleted, tuned
2001 GTP - cam, headers, nitrous, stock trans - 11.83 @ 116 <$2k in mods - sold