Author Topic: Jl8 brake option  (Read 2651 times)

KurtS

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Re: Jl8 brake option
« Reply #15 on: October 29, 2020, 04:00:11 AM »
I still own it. White, black top, L35 auto, no AC.
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69Z28-RS

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Re: Jl8 brake option
« Reply #16 on: October 29, 2020, 01:09:15 PM »
Kurt:   OK.... Not the same car.   I sent you a PM with some more info...
09C 69Z28-RS, 72 B 720 cowl console rosewood tint
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69Z28-RS

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Re: Jl8 brake option
« Reply #17 on: October 31, 2020, 01:57:15 PM »
OK, some of the information I provided previously is *incorrect*, so I'm going to TRY to correct/update here.

The facts I’ve learned this week (and seen photos) are here:
1.   The ’69 Camaro with JL8 that I've mentioned before is a Daytona yellow, black vinyl top, with black houndstooth interior (76 B / 713 ).   It is a 396/350 hp, Automatic.  It also had factory installed AC (although not complete under the hood).
2.   It’s a 10A car (checking the VIN number it appears to have been produced on 4 Oct 1968).
3.   I first saw the car around 1977 when the ‘new owner’ and his friend brought it to my home to show me the car they had just purchased from the local Oldsmobile dealer – off the used lot – it had been traded in on a new Olds.   In my ‘walk around’ examination in my driveway, I noticed the 15” Rallye wheels (unusual on a 396 car) so I checked the brake calipers.   It had the 4-piston disk brakes, including on the rear axle.  At that time, the components appeared 'original' and to have been there since its build, although I didn’t have opportunity to thoroughly check numbers etc.   I informed the new 18 yr old buyer that it had a rare disk brake option, and that I would trade the 12 bolt 3.73 posi rear from my original ’69 Z28 for the rear end AND pay him more ‘to boot’ than he had just paid for the car.   He didn’t take my offer, although until that point he had not realized it had the 4WD rear.   He has since checked all the parts and told me this last week that the car has ALL of the JL8 parts including the rear and front brakes and all worked perfectly.  It appeared to me in 1977 to be a factory install – not something converted by someone (and that was in 1977)!   He was about to graduate HS, and had told me he planned to go to college in engineering; that fact helped me to locate him years later!  

UPDATE from this past week.  I called all the numbers I had for him and left a message on his work phone (hoping he still worked there).  A few days later he called me back and we talked for awhile.   He is admittedly nervous about specific data on him or his car being put on the internet, so his name and vehicle VIN and the photos he’s sent me will not be posted here, but I will post the information from the photos simply to update and clarify the information I previously posted (from my memory and my prior conclusions).

•   The car was SOLD to the end user on 18 October 1968 (only two weeks after production), but the ProtectoPlate/Warranty card  in the AUTHORIZED SELLING DEALER PLATE IMPRINT  area stamped in red block letters is  “CHEVROLET ENGINEERING CENTER, 30003 VANDYKE, WARREN MICHIGAN”.   The original customer was also identified (Atlanta GA area).
•   The original ProtectoPlate for the car identifies the factory installed components (Engine, Trans, Rear, etc).  The original engine and trans are still installed, but the differential code shows    BM0911G1 (which is for a 3.31 non posi 12 bolt), so the JLK components were apparently NOT installed in the factory as I’d believed on my ’77 viewing.  (Question:  but were they installed at the Chevy Engineering Center???)
•   The rear differential actually installed in the car is stamped    QU0129G1.  The center section cast date is A218.  I conclude that the QU rear was assembled on 29 January 1968 which is ~ a year before the JL8 option was available for order by the public!   I became curious if this rear may have been an OTC service duty rear (rather than std JL8), but the owner believes it conforms to the JL8 diff tubes (although in my opinion, available JL8 vs SD OTC rear information is very spotty and not as concise as I would wish).   
•   The QU rear prefix specifies a 3.07 ratio Posi 12 bot with 4WD (same as what Kurt posted was in his car from factory – based on the ProtectoPlate info.  I also wondered, and queried KurtS privately if it was possible that his car and this car were purchased by the same dealer or party in Georgia, and if the complete brake systems may have been swapped between the cars for some reason but KurtS said the numbers didn’t match up.   3.07 JL8 rears have to be very rare and far between I would think!  

Conclusion:   I was able to get some more specific information about this car this last week and I found out my prior information/assumption was wrong, but it does have ‘factory JL8 components’ installed although we’re unable thus far to determine how/who/when it was installed, but it was well before 1977 based on the condition at that time.   It’s strange to me for these two cars (KurtS and this one) to both have JL8 evidences (in 3.07 form) but not match to their POPs… and both being big block cars (which most people have said didn’t get JL8 installed!)…   It’s an ‘automotive archaeological mystery’ which I’d love to know the answer to!  
09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette, '60 Corvette, '72 Corvette
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

william

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Re: Jl8 brake option
« Reply #18 on: October 31, 2020, 06:22:14 PM »
The SS396 JL8 stories have been around as long as I can remember. There have been several built-up cars passed off as original; there was another submitted to Legends judging at MCACN a few years ago. The fact remains that if you throw enough money at it, you could build one 100% technically correct. It would even have a Protect-O-Plate. But it would not have a real window sticker, shippers copy or broadcast copies.

It's a tall order, but when a 100% original SS396 JL8 car with some of those docs reveals itself, I will be the first to celebrate.
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KurtS

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Re: Jl8 brake option
« Reply #19 on: November 02, 2020, 08:03:54 PM »
Gary,
That is the in-service date, not the sales date. That's normal practice for cars that GM used. That axle is a 69 axle.
It's possible that this car was used for JL8 development - hard to tell or prove.

William,
My car is not 100% original - it has a repaint and the wrong axle and only has a POP. The car was never presented as a JL8 car by any former owner. The Tech Center stamp on the POP is an original.
I always questioned the POP, mainly cause the axle is dated exactly the same as the POP, but is a BR, not a QU. Eventually I realized that the axle is actually CBR and a year too late for the car.  What I don't know is know is when the components were swapped. I assume that someone (post-GM) swapped them out early in the car's life.
« Last Edit: November 02, 2020, 09:01:06 PM by KurtS »
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william

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Re: Jl8 brake option
« Reply #20 on: November 02, 2020, 11:50:29 PM »
I do not doubt for one minute it was built with JL8.

Problem is, the Tech Center could order virtually anything; Z/28 converts, ZL1 show cars w/special paint. Shortly after your car was delivered, JL8 was cancelled.

Did a retail buyer order and take delivery of a Camaro SS 396 with JL8 brakes? Still don't know.
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KurtS

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Re: Jl8 brake option
« Reply #21 on: November 03, 2020, 09:21:21 PM »
I do not doubt for one minute it was built with JL8.
Did a retail buyer order and take delivery of a Camaro SS 396 with JL8 brakes? Still don't know.
I've seen no evidence of that so far. All Z's with JL8 except for one L65 car and one reputed 307 car. And my Tech Center car.
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firstgenaddict

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Re: Jl8 brake option
« Reply #22 on: April 07, 2021, 08:06:19 PM »
Nicely loaded up L78 M22 fold down ZL2, F41,  car is 6526xx may have just missed the cutoff, or there were no more 3.73 JL8 axles in the pipeline, the original purchaser ended up thinking that JL8 was only available on Z28's and thus the reason his car was not so equipped...

I believe I found out the reason why it was not built with JL8.
 
The ordering customer opted for the 14" WW belted tires -JL8 stipulation specifically states it is not available with optional tires -  tires over rode the JL8 and JL8 was kicked out.
Similar to what happened on my old Lemans Blue 69 Z28 - ordered with rear antenna and D80 - rear antenna took precedence and D80 was kicked out. 
James
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KurtS

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Re: Jl8 brake option
« Reply #23 on: April 08, 2021, 01:10:01 AM »
Normally when there was a conflict, the dealer was contacted to clarify the order. Sometimes that process wasn't robust. :)

This was added to the JL8 section on the site a while back:
Most JL8's were installed on Z28's, but GM documentation indicates that 27 non-Z28's had JL8.
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