Messages

Jeff,

It's been about 6 months since the last post on this topic and I was just wondering if you've purchased your new exhaust system. Did you go with an aluminized system from Gardner or the Heartbeat City system?  How do you like what you wound up with?  DId it install without issues?  Quality of parts good?

Thanks for any feedback you'd be willing to share -- I'm in the process of making the same decision for my '69 Z28.
Chuck

The possibility that it is the dealer stock number makes good sense.  I hadn't thought of that.  Thanks Byron.

Attached is a copy of my '69 Z28's Dealer Shipper.  The car is an 05E Norwood build I've owned since 1979, when I purchased it from the 1st owner.

Can anyone shed some light on the significance of the handwritten "#227" above the handwritten key codes at the bottom of the shipper?  Thanks a bunch.

I may be able to shed some light on this.  While I'm not familiar with this specific substitution of black phospated intake manifold bolts being used in place of the silver/zinc bolts on some small quantity of 1st Gen Z28's, I am well aware of situations in which an automotive manufacturing plant temporarily runs out of a specified part and has to use an alternate or substitute part to maintain production.  In the Big 3 auto company that I retired from after 30+ years, this was called a TSA, or Temporary Substitution Allowance, and required a buy-off from Engineering.  In fact, fasteners were the most common parts for which TSA's were approved by Engineering to keep the line running while Production Control scrambled to bring in the originally specified part.  In some TSA situations, the plant had to perform an additional activity or rework in order to make the substitution acceptable.  In the case of the black phosphated intake manifold bolts being substituted for silver/zinc bolts on Z28 intakes, it is quite feasible that the Flint Engine Plant may have been told that the swap was acceptable provided they applied silver paint to the bolt heads before the engine was shipped.  In this case, the issue was strictly appearance, not function.  TSA's, or the use of Alternate Parts were, and are today, a fact of life in any automotive manufacturing facility.

My current Camaro project has been to pull together a database of all of the specifications that affect the calibration on the OEM Holley 780 carbs that Chevrolet used on the 1967-'69 Z28 302 engines, Holley List No.'s 3910, 3911 and 4053.  The database includes many key features that were never published by Holley in their Numerical Listings or by Chevrolet in their Service and Overhaul Manuals or in any of the Holley Rebuild/Tuning books out there.  This would include various calibration features Holley incorporated in each of the specific carb bodies and metering blocks for these three List No. carbs, such as: PVCR hole diameters, Idle Feed Restriction hole diameters, Idle and High Speed Air Bleed hole diameters, etc. etc.
 
The purpose for pulling this data together is to act as a definitive source that would allow owners of these early Z28 carbs to determine if their particular carb has been modified from the OEM calibration condition by virtue of a previous owner who may have gotten a little overzealous with a drill and "attacked" one or more air/fuel calibration passages in either the metering block or the main body.  I am hoping the CRG Moderator will consider posting the database, when complete, in the appropriate section on the website, as a supplement to the very helpful Holley four-barrel carb info already posted there.
 
The database is 100% complete for the List 4053 Holley, used on all '68 and '69 Z28's sold in all 50 states.  This carb was the "easy" one to do, since I own an unmolested 4053 carb.
 
However, in order to complete the database (which has become a labor of love), I could use some help from owners of unmolested 1967 Z28 Holleys: either the List 3910 carb (used on all non-California sold cars) or the List 3911 carb (used on all A.I.R. system equipped cars sold in California).  I'm hoping to find a willing soul or two who would agree to work with me, and who ideally also owns a set of small number drill bits, to carefully probe a few specific drilled holes in their metering blocks and/or main body.  To access many of these calibration holes (PVCR, Idle Feed Restriction, Emulsion Well Bleeds, Main Well Siphon Break) it will require removing the fuel bowls and metering blocks from the main body.
 
If anyone steps forward to lend a hand in this endeavor (and who has access to a set of numbered drill bits or small gauge pins covering the range from 0.020" - 0.070" dia.), I will walk you through what would be involved in gathering the missing data needed to complete the database for their specific List No. carb.  In the event a volunteer steps forward but does not have access to these small drill bits or gauge pin sets, I will mail/loan you my set to use,  although the #1-60 and #61-80 sets are very reasonable (< $30) to purchase via mail order).
 
I've been in contact with many sources to date to get the database to the point where it is today.  This includes Engineers/Techs at Holley, knowledgeable Holley people at various Holley restoration facilities, and many others.  Recently, I've been in touch with Jerry MacNeish, a long time CRG Member, who is all for completing this database as it will be of significant help to 1st Gen Z28 owners hoping to accurately restore/return their carb back to the calibration it had when it left Holley.  Who can argue with that endorsement?
 
Until such time as the database for all three carbs is complete and (hopefully) published on the CRG website, if anyone who has a List 4053 Holley on their '68 or '69 Z28 and would like to know what the original hole diameter should be of any of the metering block or main body calibration holes, just send me a private message and I will gladly help you out in any way I can.
 
Thanks for reading and many thanks in advance to anyone who volunteers themself and their carb to help complete this database.  I'm posting this in the "Originality" category as well.
 
Chuck B.

My current Camaro project has been to pull together a database of all of the specifications that affect the calibration on the OEM Holley 780 carbs that Chevrolet used on the 1967-'69 Z28 302 engines, Holley List No.'s 3910, 3911 and 4053.  The database includes many key features that were never published by Holley in their Numerical Listings or by Chevrolet in their Service and Overhaul Manuals or in any of the Holley Rebuild/Tuning books out there.  This would include various calibration features Holley incorporated in each of the specific carb bodies and metering blocks for these three List No. carbs, such as: PVCR hole diameters, Idle Feed Restriction hole diameters, Idle and High Speed Air Bleed hole diameters, etc. etc.
 
The purpose for pulling this data together is to act as a definitive source that would allow owners of these early Z28 carbs to determine if their particular carb has been modified from the OEM calibration condition by virtue of a previous owner who may have gotten a little overzealous with a drill and "attacked" one or more air/fuel calibration passages in either the metering block or the main body.  I am hoping the CRG Moderator will consider posting the database, when complete, in the appropriate section on the website, as a supplement to the very helpful Holley four-barrel carb info already posted there.
 
The database is 100% complete for the List 4053 Holley, used on all '68 and '69 Z28's sold in all 50 states.  This carb was the "easy" one to do, since I own an unmolested 4053 carb.
 
However, in order to complete the database (which has become a labor of love), I could use some help from owners of unmolested 1967 Z28 Holleys: either the List 3910 carb (used on all non-California sold cars) or the List 3911 carb (used on all A.I.R. system equipped cars sold in California).  I'm hoping to find a willing soul or two who would agree to work with me, and who ideally also owns a set of small number drill bits, to carefully probe a few specific drilled holes in their metering blocks and/or main body.  To access many of these calibration holes (PVCR, Idle Feed Restriction, Emulsion Well Bleeds, Main Well Siphon Break) it will require removing the fuel bowls and metering blocks from the main body.
 
If anyone steps forward to lend a hand in this endeavor (and who has access to a set of numbered drill bits or small gauge pins covering the range from 0.020" - 0.070" dia.), I will walk you through what would be involved in gathering the missing data needed to complete the database for their specific List No. carb.  In the event a volunteer steps forward but does not have access to these small drill bits or gauge pin sets, I will mail/loan you my set to use,  although the #1-60 and #61-80 sets are very reasonable (< $30) to purchase via mail order).
 
I've been in contact with many sources to date to get the database to the point where it is today.  This includes Engineers/Techs at Holley, knowledgeable Holley people at various Holley restoration facilities, and many others.  Recently, I've been in touch with Jerry MacNeish, a long time CRG Member, who is all for completing this database as it will be of significant help to 1st Gen Z28 owners hoping to accurately restore/return their carb back to the calibration it had when it left Holley.  Who can argue with that endorsement?
 
Until such time as the database for all three carbs is complete and (hopefully) published on the CRG website, if anyone who has a List 4053 Holley on their '68 or '69 Z28 and would like to know what the original hole diameter should be of any of the metering block or main body calibration holes, just send me a private message and I will gladly help you out in any way I can.
 
Thanks for reading and many thanks in advance to anyone who volunteers themself and their carb to help complete this database.  I'm posting this in the "Restoration" category as well.
 
Chuck B.

Thanks, Jim -- great info.  I'll give your method a try.

The COPO 9511 code was used in 1969 to specify either a 4.56 axle ratio (via 9511DT) or a 4.88 axle ratio (via 9511CB).  Without utilizing this code, the highest numerical RPO axle ratio available in 1969 was 4.10, unlike the '67 and '68 cars which anyone could order with a 4.56 or 4.88 ratio as an RPO.  I would think there were fewer 4.56/4.88 builds in '69 (vs. '67 or '68) due to those ratios no longer being an RPO -- just my guess.


Has any new information surfaced in the past decade or so that sheds light on the number or percentage of 1969 cars in the general population of all Camaros, or just the Z28's, SS's or COPO 427's, that were ordered under COPO 9511?

The plastic lens on each front park/turn lamp on my '69 have become stuck in place and are resisting removal.  In my 46 years of owning the car, neither lens has been removed.  I'd like to inspect the bulb and socket in each but I have not been able to remove the lens from either lamp assembly.  The three screws back out just fine but the lens/gasket/housing are all apparently stuck to each other.  I'm hesitant to apply any more force with a flat screwdriver than I have already tried, in fear of cracking the lens.  Has anyone had success in applying WD-40 or some other fluid around the perimeter of the lens, or found another method to help to "unstick" the lens, without staining or damaging the lens or housing?


Thanks for help on this "sticky" situation.

There has been quite a lot of discussion about the valve lash setting for the 302's cam, specifically when the original stamped rocker arms are used.  The 0.030" lash value, done with the engine hot and running, has long been the  spec as published in the Chevrolet Service Manual.  There is a very extensive paper regarding this topic published elsewhere on the CRG website.  In short, it recommends using a cold lash of 0.026" rather than a hot and running lash of 0.030" due to the specific contour of the stamped rocker arm pad that contacts the valve stem.  Additionally, in my and others experience, there does not seem to be any noticeable difference in either performance or valve train noise when setting the lash cold vs. setting the lash after the engine has been warmed up and doing it statically.  Attempting to lash the valves with the engine hot and running simply creates an oily mess that is difficult to clean up.  No serious racers I know bother with the "hot and running" method.


When using aftermarket roller tipped rocker arms on my 302 "30-30" cam, I have always set the lash at the original 0.030" spec as these types of rocker arms have a more consistent ratio throughout the entire valve lift and the need to reduce the lash somewhat is no longer necessary.  Other than the phenomenon of the OEM stamped rockers exhibiting a slightly variable ratio throughout the valve lift, which indicated a demonstrated need to reduce the lash from 0.030" to 0.026", there is never any reason to choose a different valve lash setting based on the design of the rocker arm being used. If one chooses to do this for their own reason, they should proceed with caution.

If you're unable to find a stainless exhaust system for your car that matches the original shape/looks, there is another option you might want to consider.


About 25-30 years ago, I bought a "cheapie" non-stainless chambered exhaust system w/chrome tailpipes for my 05E '69 Z.  Before installing it, I cleaned/degreased all the pipes, except the chrome t/pipes, and applied (by brush) the POR-15 High Temp silver paint/coating -- it can be sprayed with the right equipment.  This system has been on the car two separate periods of time for most of those years and the paint has not peeled or degraded in any way.  There is no surface rust showing on any of the pipes.  After all this time, and about 20,000 miles later, the system is starting to degrade from the inside out -- one small pinhole has appeared in one of the rear chambered sections.  As such, this system is going to be replaced in the next year or so, not because it looks bad, but because this internal degradation will surely continue.  I will (finally!) be treating myself to a full Gardner Deep Tone exhaust system and will consider applying the same POR-15 High Temp silver coating before installing it.  It should look good for the next 20 years and I'll be more than happy (I'm 74!).

I'm trying to document the major tuning differences in the original Holley 780 CFM carbs as used on the '67 thru '69 Z28's.  As I understand it:

   
• List #3910 was used only on the 1967 Z28, while List #4053 was used on both the 1968 and 1969 Z28.
• List #3910 used #71 primary main jets, while List #4053 used #68 primary main jets.
• Both carbs used #76 secondary main jets.
• Both carbs used a 6.5 primary power valve and a 8.5 secondary power valve.
• My original List #4053's metering blocks have 0.063" dia. primary PVCR's and an 0.067" dia. secondary PVCR's.

Has anyone measured the primary and secondary metering block PVCR dia.'s on their original List #3910 carb?
Chuck B.

I haven't yet started the car up for the first time this spring (I live in northern Michigan), so I'm not able to tell you if the new Carter pump results in the same float level as the no logo AC pump.  I hope to finish my spring "to do" list in the next week or two and then fire up the engine.  I'll report on what I find at that time.

I've had two different AC fuel pumps on my '69 Z28/302 (all OE spec engine, carb, etc.).  One pump has the "AC" logo cast on both sides of the tower and has the following ID stamping on the mounting flange: 043V40987.  There are no other ID stampings.  I ran this pump for a number of years and replaced it about 6-7 years ago -- it was running fine when removed.  The AC pump I then put on does not have the "AC" logos cast on the tower and it has the following ID stamping on the mounting flange: 40987.  There is also a faint ID stamping on the opposite surface of the mounting flange that I believe is: 059. The 0 and the 5 are very faint but the 9 is a much deeper.  I am 99% certain neither of these two pumps is the original.  Can anyone confirm what these pumps are in terms of correct replacement, or generic, or

And now to my concern:

When this second pump (no AC logo, 40987 + 059) was on the car, I found I had to a adjust the float level nut down quite a bit -- almost to the point of running out of threads, in order to set the wet float level, engine running, to dribble out the sight plug holes.  After being set, the float bowls were removed and the "dry" float setting checked per the '69 Chevy Service Manual spec's of: "Invert bowl and insert 0.350" drill bit Primary or 0.500" drill bit Secondary between float and top of bowl and adjust to achieve specified clearance."  Checking both bowls, I found the float level in each about an additional 3/32" to 1/8" lower (meaning "down" in car position)than these spec's of 0.350" Pri/0.500" Sec.  This lead me to believe this second pump (no AC logo 40987 + 059) was putting out more than the 5 - 6.5 psi spec the Service Manual calls for.  I never checked this same "dry" float spec when I had the  first pump (AC logo, 043V40987) on the car years ago and set the float level with engine running.

This week, I built a test fixture, with a rotating eccentric on a shaft, driven by a typical 3/8" drill motor.  I can bolt fuel pumps to this fixture and run supply and output fuel lines to the pump to feed fuel to the pump from a small gas can at the same level as the pump and run the output fuel down into a 2nd gas can.  The output line has a small valve I can either close or just barely open in order to have a minimum of fuel flowing through the pump and gauge system and develop pressure.  I also mounted a liquid filled pressure gauge to monitor the pressure the pump achieves.  The results of testing these two pumps are:

The first pump (AC logo, 043V40987) = 3.5 PSI
The second pump (no AC logo, 40987 + 059) = 6.0 PSI
(I also tested a 3rd pump, a new Carter p/n M4685, made in China, their '69-'71 302/350 Hi Perf repl pump = 6.0 PSI vs spec of 5-7 PSI)

I'm surprised the second pump put out only 6 PSI, well within the Service Manual spec of 5 - 6.5 PSI -- I was expecting something higher, given how far down I had to adjust the float setting nut on both bowls.

Could this be a needle/seat issue that required running the float nut down to almost run out of threads with the 6 PSI pump, even though the pump pressure is within spec?  I use only genuine Holley parts and had replaced both needle/seats at the time the second pump (6 PSI) went on the car about 6 years ago.  The float settings were set back then, engine running, dribble, and never changed, just re-checked occasionally with no re-adjustment ever required.  I suppose it's possible the two new needle/seat assy's I put in back then could have been a bit out of spec -- what else would be something to try to get a more "normal" float setting?  I might just put the first pump (AC logo, 043V40987) that tested at 3.5 PSI back on the car, but having been run for a number of years and then sitting on the shelf, I'm concerned the pump's diaphragm may have "dried out" and could fail rather quickly.

I may be chasing an issue that really isn't one, but I am curious.  I haven't seen this "low" of a float position on the many other 4150/4160 Holley's I've played with over the years.  Thanks for any wisdom provided!
Chuck

I recently purchased a set of new bleeder screws for the rear drum brake wheel cylinders and the front disc brake calipers on my '69 Z28.  The kit (from Heartbeat City) included a pair of blue plastic dust caps for the front calipers.  I checked the fit of the blue dust caps on the new caliper bleeders and found that the cap's opening was quite small and I feared the cap would split if I forced them on.  I contact Heartbeat City and they sent me a replacement kit of bleeders and caps but they were identical to the first batch.  Now that I had 4 blue caps, I went ahead and pushed one onto the new bleeder screw and it did split as I expected.  One of three things could cause this: 1.) the dust cap material currently being used by the maker is not as compliant (or stretchy) as the original material, 2.) the hole in the dust cap is smaller than the original, or 3.) the tip of the bleeder screw is larger than the original.


To fix this, I drilled a 3/8" hole through a small flat piece of 1/2" thick aluminum, to fit the body of the the new dust caps.  I inserted a dust cap into the aluminum and clamped it down to the drill press table, so that the hole faced up and the flange on the dust cap lip was clamped tight to the table and would then prevent the cap from turning when drilling.  Using a 9/32" drill bit, I then carefully drilled out the hole in the cap, being sure not to run the bit too far down to poke out through the top of the cap.  The resultant fit of the cap onto the bleeder screw felt right - lightly snug.  Perhaps the next size smaller drill bit (17/64") would also work and give a slightly tighter fit to the bleeder screw, but I went with the 9/32" bit.