My last post was as a newbie. This is my first shot at requesting assistance from the Olds faithful.
While reinstalling the heater fan housing on the firewall on my car ('68 non-a/c 442), I noticed that the fastening nuts would not tighten snugly on the threaded studs coming through the firewall, though they were the nuts that were on when the housing was removed. For all I know, the nuts may not have been very snug before. The nuts appear to be incorrect/non-original(?), as they are shallow and do not fully cover the relatively large diameter holes in the housing perimeter. Can someone provide a close-up photo or accurate description of the correct style nut?
I know this is probably not the most "fasten-ating" message sent in a while, but I'd appreciate any input. Thanks much.

 

I'm fasten-ated.

Those are "washer lock nuts", 1/4-20 thread IIRC.
In the '71 assembly manual they're part number 9419845.
Paragon Corvette has them in a kit.
https://www.paragoncorvette.com/p-34...-stud-kit.aspx

Clips and fasteners also has them, could probably find them at a good hardware store too.

http://www.clipsandfasteners.com/Nut...Lock_s/137.htm

I don't have a pic right now but the ones on my A/C box are a black flat finish if it matters.

 

Thanks much for your quick reply and help. The nut style you described is what I was thinking they should be. I shouldn't need a pic.
BTW, I've enjoyed reading your posts. And, of course, your Blue Vista is a great looking Rocket. It's interesting how wagons have grown in popularity.

 

Bluevista: Though this occurred a while ago, I just wanted to thank you for the help with the washer lock nuts. I found some which matched the description/photo of the correct item on the Clips and Fasteners site and they worked well. Now, I'm less of a "nut" case than before (at least in my opinion).

 

You're welcome, glad I could help.

 

We call those stamped steel nuts- Pal nuts...