Maybe try these

The print-o-seal are pretty soft for iron on iron.
I have had them between iron heads and alum intake and they did not hold up that good.
The Victor Reniz are very nice. They do need a little triming at the oil drains. Some people say they can't find them, but I don't have any problem getting them in Nova Scotia. They are made in Canada.






68 Mustang F/B
67 Fairlane GT