OldIHC

Looking for a locking & vented gas cap for my 56 s100. Stock non locking one is pretty beat up and want to replace. Any ideas of one that will work/fit?
Thanks

Stant 10491.

I bought this one on eBay. It fits perfectly:
https://www.ebay.com/itm/GAS-CAP-LOCKIN ... 3154560679

Gracias!

This gas cap is vented. It doesn't reflect that, in the description- but, it is. I crossed referenced the item number, to verify. I've been using this cap for over 3 months; and, it works great.

I took my 1955 R112 out for it's maiden voyage and got a 1/2 mile down the road and the truck died. The holley carb bowl was empty. It has a rebuilt carb and new fuel pump but it acted like a vapor lock. Is it possible that the gas cap needs to be vented? The truck will sit and idle for hou rs just fine and i ran it 30 minutes plus twice when i got home just fine. Let me know what you think.

This was happening to me, until I bought the vented gas cap. This, along with making sure that the truck is warmed up to operating temp, prior to driving, has eliminated any stalling.

There is no other vent in the fuel system. The vented gas cap is a must. Otherwise, if the fuel pump and lines were strong enough, the vacuum created would eventually collapse the tank. [Since it's not that strong, and doesn't collapse the tank, you simply run out of fuel when the vacuum in the tank from the exiting fuel overcomes the pressure created by the fuel pump.]

Well, it all makes complete sense, then. Thank you.

Just FYI that according to Summit the Stant 10491 is not vented .
https://www.summitracing.com/parts/snn-10491