Was the yellow OK stamp found on either the drivers side or passenger side on the front of the valve cover? Or just on the drivers side? I have a 69 San Jose Mach 1 with a 351W.
One of my main sources! Between him and Scott Hollenbeck at the 428CobraJet site. Between Jeff and Scott, I bet we had over 2,000 contacts regarding the SCJ we did.The fellow to talk to about the "paint OK" stamp is Jeff Speegle who is the moderator on Concours Mustang. You would be better off waiting to see what he says, and, also try be be at an MCA show as he often brings along the correct stamps. Better to get it done right the first time.