I finally lost my gas cap the other day (left it on the pump). It was almost 5 years so not bad. Anyone know what the measurements are for the short collar and long collar gas caps for a 1970 CA car? It's a stock tank in a CA car that I removed all of the emmissions parts from. The flare on the outer part of the filler neck is approx. 0.75" deep and the inside catch is about 0.25" deep. I had a vented cap on there before. I'm tempted to just buy all of the available factory style caps and see what fits but trying to be "reasonable" with my ex-wife (my camaro) spending.