66 fan shroud J nut

[Bob P.]

Can anyone confirm the type of J nut used to secure the fan shroud on a car born February 28 1966. Big block. I presently have hex head nuts and was told they should be square. I checked the AIM and the parts catalog. AIM calls for #3792259 "U" nut. It also has two revisions but I can't read the numbers and it doesn't have any dates for the revisions. When I looked at the parts catalog I couldn't find the numbers.

[Michael M.]

Re: 66 fan shroud J nut

Bob that is the correct part number for the U-nut. If you are going to have your car judged you have to use the U-nut. If you not going to have your car judged then any Corvette parts supplier will have the J-nut.

[Bob P.]

Re: 66 fan shroud J nut

Mike

Thanks but do you know if the nut is square headed or hex headed?

[Mike M.]

Re: 66 fan shroud J nut

the captive nut in the J-nut is of square configuration.and the repos available about 10 years ago were incorrect.mike

[Michael M.]

Re: 66 fan shroud J nut

Bob the nut had a square head with indentations on each corner. Three different types were made. One with a dimple, one with a raised rectangle, and one was smooth. All these markings or none markings were adjacent to the nut. On the bottom of the U-nut depending on what type you are looking at you will see a letter "P" or a diamond with a line in it.

[Bob P.]

Re: 66 fan shroud J nut

Someone mention to me that these nuts can be bought at Restoration Specialties and Supply. Its nut number 1018J. Is that familiar to anyone?

[Bob P.]

Re: 66 fan shroud J nut

Mike & Mike

Thanks for responding

[Keith B.]

How early is your car?

Big block j-nuts where hexed in 1965. If your car was early it could have had left over supply. There has also been s=discussion about the bolt that secures the j-nut. Some judges would suggest that a pointed bolt was used for this application. I have seen several documented low mile BB (some 5 star bowties)and have yet to find a pointed bolt that was correct. The current reproduction square nuts are close but have slight differences. Look up Camaro fender j-nuts and you will find the same configuration as for corvette shroud.

[Michael H.]

Re: 66 fan shroud J nut

Bob the nut had a square head with indentations on each corner.

That's the style of nut on my November 65 built 66. Square caged nut with an indentation at each corner.