1967 327/300 A/C Upper Alternator Brace

[Kent K.]

There have been several posts regarding the upper alternator brace on 1967 small block Corvettes. To my knowledge from information received from the (only) three previous owners, this tracing is from the original brace installed at St. Louis on my mid-production run 327/300 A/C Corvette. Images provided here and in the next post are the best I can provide with limitations present. Hopefully, this will help those who have questions or are looking through swap meets for the correct brace.

Bolt information may only be correct for my car but may be a guide for others:

Lower Bolt --- through upper, lower brackets and water pump (in that order) into engine block is a Grade 5, mfr. P, 3/8" dia. with 9/16" hex head. Threads extend approx. 1" and are 16 per inch. Overall length including threads and shank is 1 7/8" long. Cadmium plated. There is a washer but, after removing it twice, I forgot to take notes. Most likely, it is a plain washer.

Upper Bolt --- through star and plain washers, through bracket and into alternator. Bolt is 5/16" dia. with full threads (18 threads/inch.), about 1" long with a 1/2" hex head identified as a recessed head with WB mfr's marking. External tooth washer with flat cut tooth ends and a 7/8" dia. plain washer, approx. 1/16" thick. Cadmium plated.

If these two images are insufficient for you, please email me for my address. Then I would ask you send me a SASE for a full copy (legal size paper). My scanner is for letter size paper only.

Second image to follow.

Regards,
Kent Keech

[Kent K.]

Re: 1967 327/300 A/C Upper Alternator Brace

Second image.

Like Jerry,
Having fun.
Kent Keech

[Joe L.]

Re: 1967 327/300 A/C Upper Alternator Brace

Kent------

The brace that you have depicted appears to be a GM #3884640. This brace was used, at least, for 1967 small block applications without C-60. The AIM indicates brace GM #3854028 was used for C-60 applications. Among other differences, the slot length for this brace was 2-7/32".

However, while PRODUCTION information from the AIM indicates that the GM #3854028 was used for 1967 C-60 small block applications, SERVICE parts information indicates otherwise. SERVICE parts information indicates that the 3854028 was last used for the 1965 model year for certain small blocks with C-60. According to SERVICE parts information, the GM #3884640 was used for all 1967 300 hp applications, regardless of whether or not C-60 was also installed.

So, in this case, there is a conflict between the AIM information and the SERVICE parts information. Based upon what you've found, I strongly suspect that the SERVICE parts information is correct.

[Kent K.]

Re: 1967 327/300 A/C Upper Alternator Brace

Joe,

Thanks for the feedback. I see the AIM calls for #3854028. What are the other differences between GM #3854028 and GM #3884640? Could it be that the line ran out of #3854028 and substituted #3884640 when my car rolled through? Are differences so great that the substitution was uneventful? Where do you obtain dimensions/specifications for such parts?

Regards,
Kent Keech

[Joe L.]

Re: 1967 327/300 A/C Upper Alternator Brace

Kent-----

The length and offset between the two braces is very similar. However, I do not have information on possible angularity differences between the two. My strong suspicion is that the 3884640 was used for many, most, or all 1967 with 300 hp and C-60. I can't say that for certain, though.

[Gerard F.]

But The one Joe R and I have is shorter

Kent,

Same slot length but +/- 13-3/4" across the diagonal, outside to outside. From the center of hole at the bottom to the center of the hole in the slot as you show it, Joe Randolph's tracing measures +/- 12-5/8" (where you show +/- 13-7/8".

Maybe ours came off a Ford.

Having fun,

Jerry Fuccillo
#42179

[Kent K.]

Re: But The one Joe R and I have is shorter

Jerry,

My BAD, eyes-brain can't seem to remember to drop 1", 2" or 3" when measuring. The actual dimension from center to center should have been 12 7/8" (+/-). Thanks for correcting me. Taint from a FURD!!!

If you read Joe's post, there could be something awry in his parts manuals. And the assembly line may have used this bracket on A/C cars instead of the intended bracket. But, who's to know for sure unless we gain more knowledge from untouched original '67 A/C Corvettes.

Regards,
Kent Keech

[Gerard F.]

That's close enough

Kent,

I guess we all have the same one within measuring tolerances

There is no part number on them and I can hear the assembly line worker saying "Oh yea, that's the small block one!"

Wonder if it has to do with the order of assembly? Which came first, the alternator or the C60? Maybe that's the key to the mystery.

Jerry Fuccillo

[Barbara S.]

Re: 1967 327/300 A/C Upper Alternator Brace

Here's a photo of mine from the restored survivor that I completed last year. 1967 327/300 with C60.

Hope this helps.
Tony

[Barbara S.]

The photo *NM*

[Joe R.]

Re: The photo

Hi Tony:

Glad to see that you can post photos now. I know you have some great ones in your archive. This particular photo is of the A/C bracket, not the alternator bracket, but it's a great photo nonetheless.

[Joe R.]

Re: The photo

Oops, my bad. I didn't realize that I could scroll over to see the alternator brace!