Author Topic: Rear Axle BU 4 10  (Read 928 times)

ric1969

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Rear Axle BU 4 10
« on: September 19, 2020, 03:18:22 AM »
   Is it possible to have a rear axle code BU 1125 G2 with ratio 4 10 not 3 73 from factory or dealer for early 69 Z28 thanks.

69Z28-RS

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Re: Rear Axle BU 4 10
« Reply #1 on: September 19, 2020, 12:44:19 PM »
The assembly plant would not have changed gears in a rear either during or after assembly; doubt they even had the capability even if they had wanted to.

A gear change could have happened in the dealer (at customer's request), or after delivery to the customer.
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william

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Re: Rear Axle BU 4 10
« Reply #2 on: September 19, 2020, 01:48:14 PM »
Some very early production cars may have been built like that. Both ratios are listed on documents; this car had a POP listing a BU axle but appears to have been built with 4.10s.

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ric1969

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Re: Rear Axle BU 4 10
« Reply #3 on: September 21, 2020, 02:14:40 PM »
  Thanks William, i look at a early Van Nuys Z/28 has window sticker same as you shown but P.O.P and Rear Axle has BU 0920 .

69Z28-RS

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Re: Rear Axle BU 4 10
« Reply #4 on: September 22, 2020, 12:48:18 AM »
Some very early production cars may have been built like that. Both ratios are listed on documents; this car had a POP listing a BU axle but appears to have been built with 4.10s.


William, 
What 'document' is that you are referencing a portion of, which shows the STD Z28 ratio of 3.73 And an option code for the 4.10 ratio?
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
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william

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Re: Rear Axle BU 4 10
« Reply #5 on: September 22, 2020, 01:55:35 AM »
Window sticker; Car Shipper copy has the same info.

Jerry MacNeish's 1969 Camaro book has a reprint of the window sticker for Z/28 N522776 showing two rear axle ratios.
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ZLP955

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Re: Rear Axle BU 4 10
« Reply #6 on: September 22, 2020, 09:13:07 AM »
I know of an 09D LA-built Z/28 9L502xxx down here in Aus, that has the same on itís docs.
Tim in Australia.
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Sold at Clippinger Chevrolet in Covina, CA.
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william

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Re: Rear Axle BU 4 10
« Reply #7 on: September 22, 2020, 11:20:31 AM »
Do you know the history of that car? Is it restored?
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69Z28-RS

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Re: Rear Axle BU 4 10
« Reply #8 on: September 22, 2020, 11:50:07 AM »
Isn't it normal to see the 'standard and included options' for a car on the window sticker?   If the 4.10 gear option was selected as well, then that too would show up on the window sticker.

The REAL Question here (in my mind) is how would that gear option be implemented in the factory?   It certainly wouldn't be with modifying a 3.73 gear rear in the assembly plant, so the question is:   Would the gear plant pull a 3.73 rear (already built if it has the BU code stamped on it already) and replace with a 4.10 gearset and go thru that same original setup work AGAIN?   WHY would they not simply ship one of the already built 4.10 gear rears which was stamped with the normal 4.10 stamping??

I think it's more likely that at the time of the car's BUILD, there were no 4.10 gear rears available in the assembly plant (a fairly rare option), so it was assembled with the std 3.73 rear.   When the car arrived at the dealership (without one of the options - which did happen pretty often), then the customer/dealer agreed that it would be updated (modified with the 4.10 gear set) at the dealership.  I'd like to see the ENTIRE window sticker to determine if there's more information there that might help explain the issue...

« Last Edit: September 22, 2020, 01:00:11 PM by 69Z28-RS »
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

ZLP955

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Re: Rear Axle BU 4 10
« Reply #9 on: September 22, 2020, 12:47:18 PM »
Do you know the history of that car? Is it restored?
Bill I believe it's still unrestored, lost touch with the owner around 2017 soon after he gave me a chance to buy it. It's the HO Fred Gledhill car we discussed a little while back, that *may* have been a magazine test vehicle.
I queried the docs and PoP (with Kurt IIRC) several years prior to that, partly because of the axle code.
Tim in Australia.
1969 04A Van Nuys Z/28. Cortez Silver, Dark Blue interior, VE3, Z21, Z23, D55/U17, D80, flat hood.
Sold at Clippinger Chevrolet in Covina, CA.
AHRA Formula Stock at Lions Dragstrip, NHRA E/MP at Pomona Raceway

Kelley W King

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Re: Rear Axle BU 4 10
« Reply #10 on: September 22, 2020, 01:31:46 PM »
It seems Gary,s thought of 'standard and included options' sounds good maybe until someone realized it was confusing. Seems back in the day hearing cars came in with the wrong ratio was frequent, maybe the confusion was why.
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william

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Re: Rear Axle BU 4 10
« Reply #11 on: September 22, 2020, 02:24:30 PM »
Someone posted vintage pics of the Hot Rod test car engine bay on SYC. The body tag is visible and the number matches the window sticker. No question it is the Hot Rod/SCG/PHR test car.
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ZLP955

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Re: Rear Axle BU 4 10
« Reply #12 on: September 22, 2020, 08:52:53 PM »
Interesting. I must've missed seeing the engine bay pictures at yenko.net.....
I'll see if a can find another way of contacting the owner, it'd be good to keep the car's whereabouts known if he did sell, and give him the news of the history if still the owner.
I have pictures of the engine when he rebuilt it, all still standard internals.
Tim in Australia.
1969 04A Van Nuys Z/28. Cortez Silver, Dark Blue interior, VE3, Z21, Z23, D55/U17, D80, flat hood.
Sold at Clippinger Chevrolet in Covina, CA.
AHRA Formula Stock at Lions Dragstrip, NHRA E/MP at Pomona Raceway

william

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Re: Rear Axle BU 4 10
« Reply #13 on: September 22, 2020, 11:41:13 PM »
The pics were not on the SYC site; this link was back on August 24th.

https://www.hotrod.com/articles/vintage-dragstrip-test-of-iconic-1969-chevrolet-camaro-z28/?galleryimageid=933

If you enlarge and clean up one of the engine bay pics, the body tag is more legible. LOS # is 109348.

The many photos show the car was unusually equipped in addition to the mandatory Z/28 equipment:

N33 COMFORTILT STEERING WHEEL [2.7%]
U15 SPEED WARNING INDICATOR [0.9%]
U46 LIGHT MONITORING SYSTEM [0.6%]
U69 AM/FM PUSHBUTTON RADIO [3.4%]
VE3 SPECIAL FRONT BUMPER [5.2%]
ZK3AA DELUXE SEAT&FRT SHOULDER BELTS [7.7%]

In addition the test car had power steering, fairly rare on a Z/28. It did not have style trim group. Given the presence of six rare options there is virtually no chance there were 2 Z/28s configured exactly as this one.
« Last Edit: September 23, 2020, 12:27:40 AM by william »
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firstgenaddict

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Re: Rear Axle BU 4 10
« Reply #14 on: September 23, 2020, 02:27:43 AM »
How early was that car? IT was the one with the narrow rear stripe "68" layout correct?
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