Will trade my GT40P heads for comparable condition, GT40s. My 60s Mustang headers want the slant plug, I’m willing to give up the compression benefit and the plug placement benefit on these to get that. If you’ve got a good used set of GT40s I am willing to put cash above my GT40P’s to compensate if they are in superior condition. My have almost 200,000 miles on them, but were working fine and removed from their donor engine. Would also consider putting cash on top of these for a good set of aluminum slant plug heads