Bumper nuts: �67 vs. earlier C2

[Ronald L.]

[Scott S.]

Scott, not many checking their bumpers, more worried about the engine pads, LOL.

That may be true now, but wait until "Midyear Corvette Bumper Nuts: The Whole Sordid Story" hits the IMAX Theaters over the holiday and then on Blu-Ray disc early next year.


Then they'll be checkin'...

[Ronald L.]

[Gary B.]

That may be true now, but wait until "Midyear Corvette Bumper Nuts: The Whole Sordid Story" hits the IMAX Theaters over the holiday and then on Blu-Ray disc early next year.


Then they'll be checkin'...

Scott,

Sign me up for an IMAX ticket so long as it's in 3D.

Gary

[Ray G.]

Scott,

Sign me up for an IMAX ticket so long as it's in 3D.

Gary

Do you think it will be better than "Casablanca" ?

[Gene M.]

Gene,

Thanks for the info on your '67. I'll add it to my growing database of responses for '67 cars. To date, it appears to me that the 5/8" across the flats (ATF) nuts continued to be used into Dec of '66 and perhaps periodically into Jan of '67, at which time the 11/16" ATF nuts started appearing more consistently. It's true that the 5/8" ATF nuts are hard to find, but the 11/16" ATF nut in the correct black phosphate are not trivial to find either. The 11/16" AFT nuts that one can easily find in your local hardware store are zinc, or that gold-ish color if grade 8.

Gary

Gary,
The standard for 7/16" hardware changed about 1966-67. Industary standard prior to that was 5/8" hex for both bolt and nut. In fact all the other sizes of hardware still is the same. Why standards changed for the 7/16" nut to go to 11/16" hex is beyond me. Bad move in my opinion. The need for two wrench sizes for the same fastener is stupid, again my opinion.

The only 5/8" hex nut hardware I find is in old hardware store stock. Of course you have some. But 5/8" hex nuts is now not the norm in stocked 7/16" nuts.

My white 67 (#440) with it's use of both 5/8" and 11/16" hex bumper nuts, when I took it apart, supports the time frame change over.

[Gary B.]

Do you think it will be better than "Casablanca" ?

[Charles C.]

[Gary B.]

Maybe my cars time frame will help with your data gathering:

Feb 13, 1967 assembly date (110578) with 11/16" ATF nuts in all locations EXCEPT the rear bumper to body bolt and nut assemblies have 5/8" ATF nuts. I'm pretty sure all the hardware on my unrestored car is original.....

Charlie

Charlie,

Of the 18 bumper nuts at the rear (based on counting from the AIM), are any of them 11/16" AFTs on your '67?

Gary

[Charles C.]

[Gary B.]

Gary,

I probably should have been a little more specific with my description.

The 8 nut and bolt assemblies that attach the flat style bumper braces to the sides of the frame all have 11/16" ATF nuts.
The remaining 10 nut and bolt assemblies (8 from the bumpers through the body and the 2 that attach the round style inner lower braces to the rear of the frame) all have the 5/8" ATF nuts.

My 1967 AIM (which I purchased back in the 70's) shows the same part number nut in all locations, but my car doesn't agree with that.......

Hope this description is more helpful.

Charlie

Charlie,

Thanks. The next issue of the Corvette Restorer has an article on this exact topic, 5/8" ATF nuts vs. 11/16" ATF nuts on early '67 cars. And the info from your car will add a great data point to my research database.

You are correct that the '67 AIM never called for the use of 5/8" ATF bumper nuts. GM was simply using up 5/8" ATF bumper nut inventory left over from '66 and this persisted for a number of months into the '67 model year, as your car attests.

Gary