Locking Gas Cap

[FASTBACK340]

I was doing an e-Bay search for a locking gas cap for my `74 Dart. Everything listed kinda skips around 73-74. Does anyone KNOW the exact interchange? I've seen vaugely listed locking caps from $9 to $69...with no listed application for a `74.

HELP! I'm uncomfortable with open access to the fuel tank.

 

[GoodysGotaCuda]

Walked into my local pepboys with my cap and waled out witha locking one for my cuda. It doesnt twist in or anything. just pushes in and little tabs in it lock. I'll toss it on my duster tomorrow and see if it works, maybe theres a p/n on it.