What Fuel Cap Is Correct?

[Cadillac Kid]

Hello everyone.

I am going through the fuel system on my recently purchased 1974 C10 longed fleetside pickup. It has dual tanks. When I bought the truck it had two locking gas caps with no keys. I got the caps off. Im only getting the drivers side tank woking first. I preferred a locking gas cap so I ordered Stant (#10572).
It would not latch into the filler neck. I was upset after waiting for it in the mail and I tried modifying the filler neck to make it work, I know… So i probably have to get a new filler neck now. My question is, does someone have part numbers for the correct gas cap for this truck locking or non locking? When I ordered online there was many different sizes and lengths and models that all said the were compatible. So I'm out 10 bucks on this gas cap, I want to get the correct one next.

Thank you for all of the help.

Thought I would post a picture of my truck since I haven't yet.
The camper has been on the truck since day 1, so the paint on the bed is the best paint on the truck.
The other car is my daily driver, 1972 Cadillac Coupe Deville.

[cadillac_al]

Good taste Bro. I roll in a 78 Seville nowadays but had a couple 70's and a 77 Fleetwood. Those old gas caps were the body colored caps. If you look at some old pics you should know what I mean. I have seen many locking caps on these trucks so I don't know why yours wouldn't fit right. I have never used one. If your filler neck has been modified, you may need a new one. I'll bet ebay has plenty of stock gas caps and probably filler necks too. I think it is pretty cool that the camper top has been on the truck its entire life.

[Matt Man]

I would go to a oreilly and get a locking gas cap, I just replaced both of mine they will probably have one in stock. Love the caddy, I just had a opportunity to buy a 70 caddy deville 4 door but I passed on the land barge haha.

Also is your avatar picture you and David Freiburger from MotorTrend?

[Dead Parrot]

If you still have one of the locking caps with no key, take it with you to a local box parts store for matching purposes.

You probably need a non vented cap. Don't overlook the possibility that a PO changed out the filler necks with ones from later models. Trucks from the 70's were a mix of emission vs non-emission models depending on weight, engine, options and State of original sale. May impact type of filler neck and cap needed.

[Cadillac Kid]

Hello everybody. Thanks for your responses. Unfortunetly I don't have the old caps. I should have saved them, but they pretty much were destroyed. I'm going to be keeping my eyes open for a stock drivers side filler neck. My truck is from California and still sports all of the emissions equipment, so it is a non vented cap.

Originally Posted by Matt Man

Also is your avatar picture you and David Freiburger from MotorTrend?

Yes, it is. I'm surprised you could notice. I drove to Irwindale speedway at
5:00am to meet him this past January. I got to see him and his 74' C10 step side.

-Gavin