I had ordered a set of rear bumper letters for our '74 & brought them to the
body shop. The shop told me last night that the letters I bought are for a
urethane bumper not a fiberglass one.

They said that the pins on the urethane letters didn't correspond to the
holes on the fiberglass bumper. The bumper was bought on Ebay but I think
was originally purchased at Eckler's. Can anyone tell me where to get the
right letter set?

Chris,

Here's some new GM 74 and 75 letters on eBay but they might be the same thing you have.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem& ; ;category=33643&item=8056711341

rearn2go7238832.5272916667

HUH?!!
Sorry, but it sounds more like someone drilled the holes wrong in the bumper cover. I have a 'glass bumper cover on the rear of my '74, and the factory style letters fit it just fine.
The covers come with no holes in them so they have to be drilled to install the letters. There are little "dimples" in the bumper where the letter pins go, as a guide to where to drill. Sounds to me like somebody goofed up on drilling the holes the first time.
You may need to have them fill in the holes that are there now, and re-drill. (Just an idea.)

I agree with Joel. Even if the holes were not filled in, the letters should cover. Fiberglass covers were not even thought of when your 74 was built. As long as the letters fit the indents, use them.

You guys have nailed the problem exactly. Apparently the problem was that
the letters' pins are not long enough for the nuts to fit on. I think they filled
in the holes on the underside of the bumper & that's why they're short.

We're either going to glue them on or the guy working with the car has
suggested that there are some type of fasteners that can attach the pins in
the same way that a soldier would attach ribbons to his uniform.

I'll let y'all know what happens.

Regular type emblem clips should work OK. The original letters also had a small amount of pookie(like dum-dum) to keep them from rattling around back there. Good luck with your bumper install!!

Thanks Joel. The rear bumper has been a miserable installation but I'll save
that story for Pigeon Forge. I'll need a couple beers for that one.

after you get the pins put in the bumper is relatively the easiest to put on the car.  will it be done for the PF trip?  like to see how many '74 vettes show up.

Jeremy, I'll be there, fer sure!