Guy at the Springfield swap meet ripped my repro radiator cap, and I still think he was wrong
Two summers back I had a table at the Route 66 swap in Springfield, and a guy named Dale picked up my repro cap and told me anything not stamped with the original part number is junk that will boil over on a hill. I run one on my 55 Chevy and it has held 13 psi for 4 seasons, no seep, no drip. He kept saying original or nothing, but half the "original" caps at that meet are stamped fakes from overseas anyway. So who is really the purist here, the guy checking numbers or the guy checking the seal?
So how do you actually tell a real stamp from a fake one if the fakes get the numbers right? Seems like Dale's whole test falls apart unless he's got some other way to check. Makes you wonder if he ever popped a cap on a pressure tester before giving you grief.
You ever watch two guys argue over a stamp for twenty minutes straight? My buddy Lenny bought a "real" NOS cap off a vendor at that same Springfield meet, numbers looked perfect, guy swore it was the real deal. Two weeks later Lenny put it on a tester and it let go at 9 pounds, gasket was rock hard and the spring was shot. Meanwhile the repro he tossed in a drawer held 14 all day long. So yeah, Dale can check numbers all he wants, but a stamp doesn't hold pressure, the spring and seal do.