VCCA Home Forums TECHNICAL - GENERAL Radios, Tools, Accessories Need help identifying locking gas cap

Have a locking gas cap produced by a Detroit company that called themselves "The Original Equipment Line." It's labeled on the box as fitting 1958 Chevrolet only, but I know 1959 was the same, so this item dates from late 1957 or 1958.

The cap was restyled for 1960, assigned a new part number, and made by another supplier thereafter.

Question I have is does anybody have a copy of the 1959 Chevrolet Accessories Reference Guide for salesmen ("know your product"), and does it have an illustration of the 1958/59 original p.n. 987741 locking gas cap? If so, what does it look like? How many keys were supplied?

TIA for hints anybody can provide.

The 987741 gas cap is flat on top with about a 1/2" flange on the side. All smooth chrome - no ridges, etc. It has a 5 tumbler lock and came with two keys. The keys had round heads.

Thanks, Chev Nut. I hope you're not describing the pn 988270. That's also a smooth, slightly rounded crown but with no side flange, just a 1/2" essentially cylindrical side surface that tapers inward slightly at the mating surface to the filler neck.

On the 1959 cap, is the keyway open, then, or is there some kind of cover to keep dirt and moisture out? The usual kinds of covers I've seen are
1) the internal one found on modern car door locks, for instance, where the you push the cover away as you insert the key, and the cover retracts inside the lock cylinder, and hence is nearly invisible with the key inserted. This is what the 1960 locking gas cap uses evidently,
2) a flip-up keyway cover,
3) an offset rotating key cover, usually spring-loaded, that is attached to the crown of the cap with a rivet. The cover can be cast and chromed, but is sometimes just a lightweight rustless steel disc.

Also, would you happen to know if the lock cylinder is pin tumbler or wafer tumbler type?

Chevgene, the 1/2" flange you describe . . . is that at a nearly 90 degree angle to the upper surface of the cap?

On what document are you basing your description, or do you have an NOS one of these in the GM box?

Would you be able to post or email a photo of this gas cap?