1964 (from ~4/1964) -1967 Headlight Bezel Screws

By way of background, the headlight bezels for 1964 through 1967 Corvettes are stamped steel metal pieces that surround each pair of headlamps. Each bezel is secured to its headlight bucket using four screws. The following is a portion of the sketch from the Corvette Assembly Manual that shows the driver’s side headlight bezel and the attaching screws.

Notice that there are two screws that insert vertically from the bottom of the bezel (labeled as item 17 in the AIM sketch) and there are two screws that insert horizontally near the top of each side of the bezel (labeled as item 19; the #19 screw on the inboard side is not shown in the sketch). Over my 20+ years of observing Corvettes judged at NCRS Chapter events I’ve been amazed at how many cars have incorrect bezels screws. The main reason this happens is that the reproduction parts companies sell the wrong screws. Owners restoring their cars who buy a set of bezel screws from any of the national catalog companies typically only find out the bezel screws are incorrect when they have their car judged. For example, here’s a screen capture from the Zip Products website. As you’ll subsequently see, the Zip screws are not correct in several obvious ways.

The bezel screws sold by Corvette Central are also wrong, but for several different reasons. For one thing, they are all black.

After substantial research, observation of Bowtie cars and searching, I have sourced screws that will pass judging. First some background on the screws in question. (If you have a ‘63 or early ‘64 Corvette, the bezel screws were chrome with oval heads, and I don’t have those screws.) From around April of 1964 through 1967, the vertical screws that insert thru the bottom of the bezel are GM 9420683. The horizontal screws that insert through near the upper corner on the sides are GM 9420684. Although the part number for those screws differs by a single digit, the two screws actually have little in common.

Here are specifications for the 64-67 bezel screws:

GM 9420683: #8-32 x 1/2” machine screw, flat head Phillips, Type C, black phosphate

GM 9420684: #8 x 1/2” sheet metal screw, flat head Phillips, Type AB, zinc plated

For those of you who like to purchase NOS parts, be advised that GM 9420683 was never available as a service replacement part. It was only used on the production line. The companion screw, GM 9420684, was discontinued from service in March of 1970, so the chance of finding NOS examples of that screw is slim to none.

Here is a photo of the two screws that I have sourced to replaced GM 9420683 and 9420684.

The replacement screws that I found for GM 9420683 (at right in the above photo) differ slightly from the original GM screw, but in a way that is not detectable once installed. First of all, the 8-32 machine screws I have do not have a Type C tip. Type C is a fastener specification for a slightly tapered, but blunt tip, with a thread cutting groove. A thread cutting tip was only needed when the screws were threaded into the receiving hole in the headlight bucket for the first time. Secondly, my 8-32 machine screws are black oxide, whereas the original GM screws were black phosphate. Black oxide is very similar to black phosphate, but black oxide offers significantly better corrosion protection.

To the best of my knowledge, the replacement screws that I found for GM 9420684 (at left above) are identical to the original GM screws. The original GM screws have two uncommon features. First, the Type AB refers to a greater number of threads per inch, 18 instead of the more common 15, for a #8 sheet metal screw. Secondly, based on my measurements of original ‘64-‘67 side screws, even though the screws are a #8 thread size, the head diameter is a #6. (As an aside, reduced head diameter screws were also used to secure the center console trim during the C2 era.) In the case of the headlight bezel screw, a reduced head diameter was used so that the side screws nest slightly further into their conical holes and don’t protrude past the surface of the bezel. That smooth nested look is quite apparent to the eye. To the best of my knowledge, the side screws sold by the reproduction parts companies either do not have a reduced diameter head and/or they are not 18 threads per inch.

The cost for a set of eight bezel screws, 4 of each type, is $20.00, including shipping to US destinations only. For payment, cash, check, or PayPal is accepted. Sorry, no credit cards.

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