Have been having some difficulty in sourcing the Correct Fuel/Gas Cap for a 1974 Dodge W200 Power Wagon with In-Cab (behind seat) Gas Tank.

The Stant # 10742 Cap sort of works, but it does not stop securely to seal (tightens then as you turn a bit more loosens again.) I suppose it could be a problem with the filler neck, but it looks to be Ok.

When you look for the correct part online at auto parts stores, their disclamer reads roughly "Note: cap does not fit in-cab tanks."

Does anyone have experience with this and/or Part Numbers and sources of caps that look "original" and/or at least function (as in stops in a sealed position.)

Thanks