'67 Big Block AC Compressor Brace Bar

[Mike B.]

Good Evening Guys,

Yes, I've inquired about this brace rod in previous threads before but here's a new question.......

Was this AC compressor brace #3894366 used on later Corvette 427/454 models? Or was it '67 only? What about other GM cars?

I'm attaching a photo posted by Peter Miller from one of my older threads. Thanks again Peter.

Mike

'67 BB AC Compressor Brace Rod #3894366.jpg

[Joe L.]

Re: '67 Big Block AC Conpressor Brace Bar

Good Evening Guys,

Yes, I've inquired about this brace rod in previous threads before but here's a new question.......

Was this AC compressor brace #3894366 used on later Corvette 427/454 models? Or was it '67 only? What about other GM cars?

I'm attaching a photo posted by Peter Miller from one of my older threads. Thanks again Peter.

Mike

[ATTACH=CONFIG]98612[/ATTACH]

Mike------


GM #3894366 was applicable only to 1967 Corvettes with C-60 and L-36/L-68. It was discontinued without supersession in February, 1976.

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

Thanks Joe. I was hoping you'd respond to this question. Sure wish I had half the data you have on original GM part applications.

So now I'm sure that these brace bars were only manufactured for two years. The brace #3894366 shown earlier in this thread and it's very close cousin for '66 #3887168 shown here.

There's an engineering drawing of the '66 #3887168 brace in Noland Adam's Resto Guide where he describes the new AC combination with the '66 427 engine. I'm wondering why GM changed these '66 style brace bars to the ones used in '67?

Here's a good shot of an original '66 #3887168 brace for anyone wondering what the difference between the two are. Mike

'66 BB AC Compressor Brace Rod #3887168.jpg

[John R.]

Re: '67 Big Block AC Conpressor Brace Bar

Mike, always enjoy your posts! I see the one end (right side in your photos) of the brace is shaped differently between both years. What else is different?

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

Good Morning John,

I'm glad this thread has laid out the way it has so the guys can make a quick comparison between these two brace bars. Thanks to Joe!

I'm still here in South Florida and the cars/parts are up north. From my memory, the '67 and '66 bars feel more solid and heavier than the repros. The biggest difference that I can tell is the rod end that attaches to the "ear" of the compressor. As seen in these photos, the '67 rod end has a more "boxed" look than the rounded shape that the '66 rod has. Maybe the engineers thought the squared '67 shape was stronger? Don't know. I'll have to lay the two that I have over each other. My '67 bar is nice, but the photo of Peter's brace compared nicer to the '66 photo I had. I think the long adjusting slot at the intake bracket is slightly different also.

Both my original '66 and '67 braces that I have are stamped with "MW" halfway down the rod underside. Careful......so are the repros. I've heard that "MW" stands for "Midwestern". Not sure. I'll include stamp shots from the '66 and '67 bars next.

I'll bet you'll find one of these original braces in that big warehouse of a shop you have! Always a pleasure John.

Take care. Mike

[Peter M.]

Re: '67 Big Block AC Compressor Brace Bar

Mike,
You need to be getting that car back together!
Kind regards

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

Hi Peter,

Yes, I was gonna retire in 2 years and dedicate my time to the old girl. My 401K no lookie so good at the moment!

We'll see about retirement sooner than later. Oh yeah.......we're gonna move down here to Florida in the near future. That's gonna slow things down too! In the meantime, I'm still collecting all the goodies she'll need for her resto.

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

OK Guys,

Here's some excellent shots that my good buddy David Harris sent me of his '67 L36 AC coupe's intake bracket and brace rod. Nice to see original stuff. We're still debating the originality of the two long intake bracket bolts. Maybe...maybe not?

The intake support bracket #3872726 is correct and was installed on '66 and '67 427 AC Corvettes. David's brace rod to support bracket adjuster bolt headmark "AS" is a correct application. Numerous headmarks found here. This #3872726 bracket was installed on other GM big block AC cars at that time as well. I've seen numerous examples of them for sale online. Many of them have "RSC" bolts installed there. Maybe I'll choose that logo?

Here's the photos from David. The bar was purposely installed backwards for ease of photography. Nice closeup of the "MW" stamp here. Mike

David Harris '67 Intake Bracket & Brace Rod Shots (AA).jpgDavid Harris '67 Intake Bracket & Brace Rod Shots (BB).jpgDavid Harris '67 Intake Bracket & Brace Rod Shots (CC).jpgDavid Harris '67 Intake Bracket & Brace Rod Shots (DD).jpgDavid Harris '67 Intake Bracket & Brace Rod Shots (EE).jpgDavid Harris '67 Intake Bracket & Brace Rod Shots (FF).jpg

[Joe L.]

Re: '67 Big Block AC Compressor Brace Bar

The GM #3887168 was discontinued from SERVICE in April, 1971 and replaced by the GM #3894366. So, GM considered them functionally equivalent.

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

Thanks Joe. Great Info.

So, I'll wrap up the photos with a few more of an original '66 #3887168 brace bar. Still wondering why GM changed the '66 production brace from #3887168 to the '67 brace #3894366? Making both of these brace rods unique to their year.

I would really appreciate any and all photos related to these '66 & '67 brace rods no matter what they may entail. Hard to find good photos of these braces loose or installed. Please post them here or send me an email. Thanks in advance!

Here's the '66 brace rod front and back and it's "MW" stamp. Mike

Mike's '66 Brace Bar (1).jpgMike's '66 Brace Bar (2).jpgMike's '66 Brace Bar (3).jpg

[Daniel Y.]

Re: '67 Big Block AC Compressor Brace Bar

Good Morning John,

I'm glad this thread has laid out the way it has so the guys can make a quick comparison between these two brace bars. Thanks to Joe!

I'm still here in South Florida and the cars/parts are up north. From my memory, the '67 and '66 bars feel more solid and heavier than the repros. The biggest difference that I can tell is the rod end that attaches to the "ear" of the compressor. As seen in these photos, the '67 rod end has a more "boxed" look than the rounded shape that the '66 rod has. Maybe the engineers thought the squared '67 shape was stronger? Don't know. I'll have to lay the two that I have over each other. My '67 bar is nice, but the photo of Peter's brace compared nicer to the '66 photo I had. I think the long adjusting slot at the intake bracket is slightly different also.

Both my original '66 and '67 braces that I have are stamped with "MW" halfway down the rod underside. Careful......so are the repros. I've heard that "MW" stands for "Midwestern". Not sure. I'll include stamp shots from the '66 and '67 bars next.

I'll bet you'll find one of these original braces in that big warehouse of a shop you have! Always a pleasure John.

Take care. Mike

Mike, I have a January 67 L68 - looks like your 66 version. I wonder if the change went through about then or maybe the mold cracked and had to start over and the design changed slightly?

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

Good Morning Dan,

When I bought my '66 back in 1988 the AC compressor and all of it's brackets were missing. Believe me, I've done quite a lot of research on the compressor and brackets that I needed for my Dec. 1st, '65 built AC L-36 convertible. All that said, I am by no means an expert on the subject. Just a well informed '66 L-36 AC guy.

Both of these compressor brace rods are what I would consider to be rare parts. Tough to find. That's why I seem to see as many repros on cars as real ones. Based on the engineering drawing I've seen in Adams book, the '66 brace that I bought and am showing here has the rounded end that mounts to the compressor. So do the repro bars. But they have noticeable differences from the one I show here.

It wouldn't surprise me at all if leftover '66 L-36 compressor brackets wound up on '67 L-36/L-68 cars. Especially the earlier built '67s. I have Corvette friends with early built '66s with leftover '65 parts factory installed. Always difficult to explain these differences to the judges.

I'm wondering the same thing as you. When did the '67 style brace rod #3894366 actually come into service? Right from the start of '67 production or "phased-in" with leftover '66 style brace rods #3887168? This is what's great about the discussion board. Always interesting things to compare.

Either way Dan, your brace bar is unique and difficult to find. I would really like to see any photos you have of it!

Mike

[John R.]

Re: '67 Big Block AC Compressor Brace Bar

Mike, here are some photos of my bracket. It was missing from my 1967 L36, so picked up at a swap meet. Obviously I can not say it was original to the car, but I am hopeful it is correct for 1967.

[Mike B.]

Re: '67 Big Block AC Compressor Brace Bar

Thank you John for resurrecting this thread from dreaded page 2 and beyond.

Your brace bar sure looks like an authentic '67 #3894366 brace bar to me. Real nice shape too. Nice find!

Now if only you '66 L-36 AC owners would post a shot of your brace bars. Someone must have a loose one handy! Mike

[Richard S.]

Re: '67 Big Block AC Compressor Brace Bar

Evening Mike...Here are a few shots of the brace on my 66, built early Dec /65, hope this helps your search.IMG_1325.jpgIMG_1326.jpgIMG_1327.jpg