72 spoiler bolt info.

[Ken C.]

i did a search on mounting bolts for front spoilers. i found a picture from patrick hulst from may 07.
My question is the nut flared out on one side or is there a washer. Tough to tell by photo.
Also is their a special head marking or does it make a diff as long as its black oxide.
thanks in advance

[Terry M.]

Re: 72 spoiler bolt info.

Nut has built-in washer.

I don't know about head marks, but in general it is a mistake to say that one certain head mark is used in any location. The head mark identified the fastener supplier -- which may (likely) changed during the course of production. The best one can say is that certain head marks are period-correct for Corvettes.

[Ken C.]

Re: 72 spoiler bolt info.

thanks terry, i thought so on both questions. Just wanted to make sure.

[Don L.]

Re: 72 spoiler bolt info.

On the issue of front spoiler (air dam) attachment hardware, does anyone know the correct direction for the 2 inner bolts/nuts? My '72 AIM shows the bolt going in from the front (against the body) , leaving the nut inside, however, I have seen numerous "original" cars, all having the nut show from the front and the bolt in the back. One of 'ems right...

[Terry M.]

Re: 72 spoiler bolt info.

Believe the cars. This is one of the errors in the early C3 AIM -- or maybe the UAW workers didn't follow the rules.

[Chuck S.]

Re: 72 spoiler bolt info.

thanks terry, i thought so on both questions. Just wanted to make sure.

Those fasteners are 1/4-20 X 5/8" long, with a flanged nut, and as I recall, a flanged head. Finish is black phosphate. No (separate) washer is used, nor does the AIM show one. UAW may have experimented with easier ways to do things...I doubt they would arbitrarily leave off a specified item.

As Terry said, several headstamps could be possible during the 70-72 period...my 70 Corvette, in fact, had three of one head stamp and another of a similar headstamp. This demonstrates GM's method for stocking fasteners in bins alongside both sides of the work stations. Confirmation of this practice was provided by John Hinckley in threads years ago...if you're lucky, you may be able to find it in the archives.

No attention was given to matching headstamps...whatever the assembly worker's hands fell on was what was used, and the bins were constantly being resupplied and intermixed with new stock that could have different headstamps. The headstamps being supplied for 71 or 72 may have been the same, or totally different...I can't offer any help on the other years, or even on 70 other than late late.

Three of my spoiler fasteners had a capital E with radial lines at 12, 6, and 9 o'clock. The fourth fastener had a smaller capital E with radial lines at 12, 3, and 6 o'clock, with a circle enclosing all the marks. These fasteners were all made by the same company, and are all Grade 5, but the change in radial line positions apparently represents some difference in specification.

I don't know if the information is still generally available, but it would be interesting to learn all the nuances of fastener headstamps during those years. Some of the markings are, no doubt, industry standard, but some of the meanings may be manufacturer specific...I wonder if some of those companies are even in existence now.

[Jack H.]

Re: 72 spoiler bolt info.

Often, the drawings in AIM books are 'approximate' intended as internal communication between design and production with the production folks left free to 'methodize' the assy process as they deemed best/most efficient.

Most of the Shark cars I've seen that were reasonably 'untouched' had the front spook attaching bolts installed in the opposite direction to that shown in the AIM pictorial...

[Reba W.]

Re: 72 spoiler bolt info.

The issue of the spoiler bolts has been addressed in the last two editions of the JG, and I believe in earlier ones.