Author Topic: 1969 exhaust question  (Read 4648 times)

aaronz28

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1969 exhaust question
« on: April 26, 2009, 03:50:44 PM »
hi, got a Sept69 build Z28.

currently have Gardner Chambered on it, but I want to put the correct system on, which I read to be the transverse with resonator system per Jerry's book.

Are there any documented cars built much later than the official change over that did not have resonators?

i'm only asking becasue I want my car to be as correct as possible, but would rather not put the resonators on.

car currently has headers so it isn't a big issue at the moment, but i plan to do some showing this summer and if I take the headers off, i'm gonna put the correct exhaust back on.

Thanks

Aaron

william

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Re: 1969 exhaust question
« Reply #1 on: April 26, 2009, 06:28:39 PM »
The configuration of the OE exhaust system was coded on the chassis broadcast sheet box 198. Very few of these sheets exist; mostly it is the body broadcast sheet found in LA built cars. I have data showing 4 LA Z/28s all with "FM" systems spanning mid-January through April builds. A July Norwood Z/28 had "FS". There are no physical markers to indicate which exhaust system a car was built with.

The standard 1969 Z/28 exhaust system was initially the noisy & restrictive chambered set up. With small tubing, 4 mufflers and lots of bends it doesn't get much worse. When the noise complaints started to mount as of November 25, 1968 it was dropped as standard equipment. Owners that had been ticketed for excessive noise could have the system replaced at no cost. The interim replacement system was the single transverse muffler with no resonators much like the 67-68 Z/28 "deep-tone" dual exhaust system. This was also used in production for a short time. The Chevy recall notice goes on to state that by "approximately April" all Z/28s would be built with the muffler/resonator system and those that did not have resonators should be retrofitted. The problem with the April date is the undercarriage photos of the 02D-built ZL-1#3 that appeared in a 1969 road test. The photos show the muffler/resonator system; other than the manifold pipes the system is the same one the Z/28 used. This indicates the resonator system was available in assembly plants much earlier than the notice states.

Based on the dates Chevy stated in the notice and what has been learned over the last 40 years it is virtually a certainty that a September 1969 built Z/28 would have had the muffler/resonator system with chrome tail pipes.







169INDY

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Re: 1969 exhaust question
« Reply #2 on: May 02, 2009, 03:58:00 PM »
William,,

The FM denotes which system.
I have "FM" in the block 198 of my remaining portion of the sheet found on top of the tank from my 04C-LOS "Z11"

Jim
Jim
68 SS/RS L35 Th-400 LOS
69 Pace Car L48 Th-350 LOS

69Z28-RS

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Re: 1969 exhaust question
« Reply #3 on: May 02, 2009, 05:46:35 PM »
William:  I'd suggest that 'magazine road test cars' are not necessarilly representative of autos that are 'right off the assembly plant lines'....  :)
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

aaronz28

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Re: 1969 exhaust question
« Reply #4 on: May 02, 2009, 05:58:29 PM »
ordinarily, I'd agree with this statement, but the ZL1 he is referring to is a well documented car and clearly lends credibility to this topic. Additionally, that car was right off the Berger Showroom floor.


william

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Re: 1969 exhaust question
« Reply #5 on: May 02, 2009, 06:44:36 PM »
The #3 ZL-1 Camaro was not a 'magazine road test car'. It was ordered for stock by Berger Chevrolet along with a number of other COPO Camaros. It was delivered to them and remained in their inventory for some time. HP Cars magazine was looking for a ZL-1 Camaro to test and Berger agreed to it. The test was conducted in MI of course and the barren trees in the background of the dragstrip photos indicate the test was conducted early Spring 1969. The car still exists in original condition and there is no reason to think it was anything other than a production 1969 Camaro. Curiously, with a body number lower than the #1 ZL-1 it has to be the first one ordered.

I am aware that some of the magazine road test cars were supplied by the zone and may have been massaged a bit. Pontiac was notorious for this-the famous Car & Driver '64 GTO actually had a 421. Chevrolet doesn't seem to have messed with their zone cars at all and may have not been all that co-operative as other magazine Camaros had to be supplied by dealers. The L89 SS-RS PHR featured came from a dealer as did the Z/28-RS HP Cars did.

Car & Driver asked for and was supplied the Ultimate Ringer-a '68 Z/28-RS with JL-8, K-66 and a cross-ram. Despite street tires and 260 lbs over the SCCA minimum weight it managed to turn lap times at Lime Rock that would have qualified it for the middle of the starting grid for the T/A race there. Probably not a production 302.
« Last Edit: May 02, 2009, 09:27:15 PM by william »

SH69Z28

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Re: 1969 exhaust question
« Reply #6 on: May 05, 2009, 08:10:03 PM »
Hi William, you've been a wealth of information as has this entire site. Anyway, I have a 1969 Z/28, 05A Los Angeles build date from which I saved the chassis broadcast sheet (or most of it!). In box 198 I see the letters "FQ". Anything special you can tell me about the correct exhaust system it came with? Thanks.
69 Z/28 Fathom Green, mostly correct with chassis broadcast sheet
69 Z/28 Dusk Blue, incorrect drive train, my driver

william

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Re: 1969 exhaust question
« Reply #7 on: May 05, 2009, 11:02:39 PM »
An 05A Z/28 could have had chambered [optional at the time] or the standard muffler/resonator system. It is close to the introduction date for chrome tailpipes but not close enough. The Z/28 with the 'FS' system would almost certainly have been equipped with the muffler/resonator/chrome tail pipe system. The codes may have changed for engineering revs not visually apparent. There are so few Chassis Broadcast Copies researching them is futile.

Thanks for the kind words. After 34 years, still not tired of it!

Mark

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Re: 1969 exhaust question
« Reply #8 on: May 07, 2009, 03:08:57 AM »
For what its worth the number 1 and No. 2 ZL1's  have an FS designated exhaust system on their build sheets.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

l88z16

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Re: 1969 exhaust question
« Reply #9 on: May 09, 2009, 08:17:59 PM »
Would part# 3961396 be the correct muffler for the standard exhaust system?If not what would 3961396   be correct for??Thanks

1968RSZ28

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Re: 1969 exhaust question
« Reply #10 on: May 10, 2009, 01:43:57 AM »
Would part# 3961396 be the correct muffler for the standard exhaust system? If not what would 3961396 be correct for?? Thanks.

My Chevrolet P&A has this description for part #3961396...

3.701    MUFFLER ASSEMBLY, Engine Exhaust

69 CHEVY, CAMARO w/ dual exh. (exc. H/Per., Sp. H/Per.)

Paul

KurtS

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Re: 1969 exhaust question
« Reply #11 on: May 10, 2009, 02:53:19 AM »
The FM denotes which system? Jim
In box 198 I see the letters "FQ". Anything special you can tell me about the correct exhaust system it came with? Thanks.
FM and FQ are both codes for the standard SB dual exhaust system.
Kurt S
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l88z16

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Re: 1969 exhaust question
« Reply #12 on: May 10, 2009, 02:56:49 AM »
Would part# 3961396 be the correct muffler for the standard exhaust system? If not what would 3961396 be correct for?? Thanks.

My Chevrolet P&A has this description for part #3961396...

3.701    MUFFLER ASSEMBLY, Engine Exhaust

69 CHEVY, CAMARO w/ dual exh. (exc. H/Per., Sp. H/Per.)

Paul
Thanks Paul.I guess that would rule out L78 and Z28.

1968RSZ28

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Re: 1969 exhaust question
« Reply #13 on: May 11, 2009, 05:06:47 AM »
Thanks Paul. I guess that would rule out L78 and Z28.

Yup.

Paul