There wasn't an oil pressure gauge option in '65 and the housing isn't designed for a gauge. It has a big hump inside that holds the idiot light. Redline said they could cut the housing away and fabricate a bracket to hold an oil pressure gauge. The guy I talked to said they had done it before but that it would be an expensive conversion due to all of the custom fab work. I'm thinking I'll just have them do the standard rebuild work and live with the idiot light. The EFI system has oil pressure on the screen so I don't really need it in the dash. Here is an inside shot of one of my spare instrument panels. You can see the bump in the housing for the oil light. All of that would need to be cut away to put a gauge in there.