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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.

Many thanks to GMAD_Van Nuys for posting the link to the earlier "heater hose clamp/alternator bracket" post -- it was quite informative.


It would appear the AIR pump hose is supposed to route between the two heater hoses.  On the other hand, the use of the alternator bracket mounted heater hose clamp beyond the April '69 timeframe remains an open question for discussion.  I've owned my Norwood 05E, offline ~6/2/69, '69 Z so long (am 2nd owner since Nov '79), I simply can no longer recall if that heater hose clamp was on the car when I acquired it or if I added it, thinking it should be there on every '69 Z28 because I saw it in an underhood photo.  Based on the info in the earlier post, I would have to guess it is more likely that I added that clamp myself at one time.


Thanks to everyone who chimed in  -- much appreciated!

Good magazine road test photos.  It's interesting that the August '69 photo (without the heater hose clamp) shows a plastic strap securing the alternator wiring to the 3/4" heater hose, while the January '69 photo (with the heater hose clamp) does not show this plastic strap.  This is just another indication of my years of experience working in the automotive industry that proves anything can and likely has happened in a vehicle assembly plant.


Although neither photo is definitive in the routing of the AIR pump hose, it leaves the door open to the possibility that it is routed between the two heater hose, rather than behind (rearward) both hoses.  Any chance there is a photo in your collection of such '69 Z28 road test photos that would allow one to draw a conclusion for the AIR pump hose routing?

On 1969 Z28's, does this photo show the correct orientation of the heater hoses in the hose support clamp attached to the alternator bracket?  Specifically:


1.  Should the 3/4" hose from the water pump be positioned in the hose support clamp in front (i.e.: closer to the alternator) of the 5/8" hose to the intake manifold?  I believe that is the correct routing through the hose support clamp.


2.  Should the hose support clamp on the alternator bracket be bent downward a bit to give some clearance to the AIR pump hose as it traverses from the driver's side AIR pump check valve to the diverter valve on the passenger side?


I have been unable to locate a clear graphic of this issue in the '69 AIM that confirms the correct hose/support bracket condition.


I've found that the AIR pump hose will be deflected rearward, into the ZL2 air cleaner (not shown),[size=78%] [/size]by interfering with the 5/8" heater hose if the heater hose support clamp on the alternator is NOT bent downward.  But, if the support clamp is not supposed to be bent down, then the AIR pump hose assumes a more "natural" routing if it is positioned between the two heater hoses, rather than behind both hoses.


I would appreciate any thoughts on this.  Thanks.

Thanks, Kurt, for providing that link.  I chased my way completely through it (and another linked imbedded therein) and came to the conclusion my late 05E car, with its VIN that calculates out to be an "off the line" date of Monday, June 2nd, may or may not have had this clip installed at Norwood.  So this is an easy decision for me -- I can look for a $500+ original clip, or do nothing and be correct.


Having said that, and being a retired chassis development engineer for one of what we use to call "The Big 3", I went right out and bought the $22 repro bracket the moment I discovered it in the '69 AIM.  In my experience, the right type of vibration (frequency and amplitude), for a sufficient amount of time, can loosen any joint, no matter how expertly tightened or how perfect (or imperfect) the mating parts are made.  Given the significant mass of the brass Y-block hanging several inches off the carb, I can see why the Chevy chassis engineers developed and released this support bracket for production -- to "calm" things down at the joint between the fuel tube nuts and their terminus at the carb and Y-block.  It would never have been released if they didn't eventually see actual evidence of its need.  This bracket can legitimately be called a "critical safety" part, in the same manner as the innocent looking clip that retains the brake booster clevis pin in the brake pedal.  This brake clip should rightly be considered the single most important part on the car. If it were not there, or if it failed, one's very life comes into jeopardy.  An undiscovered, top of engine fuel leak, no matter how small, is in the same category and is to be intelligently avoided, and easily can be, for a mere $22.  In my humble opinion, every owner of a '67-'69 Camaro with an engine that utilizes the brass Y-block would do well do install this support bracket.  Sorry for preaching, please forgive my impertinence.

The 1969 AIM on page A3 of the Z28 UPC section shows this clip, or bracket, 3959444 and screw.  It is wrapped around the fuel line going to the rear float bowl.  I assume its intent is to help control the vibration/weight of the fuel line and brass junction block ass'y.  It is attached under the rear passenger side Holley carb mounting nut.  I did a forum search of "bracket 3959444" and "clip 3959444" but no results were returned.  Even though the '69 AIM is clear in its use, and was added to the AIM in late Oct of 1968, I have not come across any photos showing it on restored cars or in posts from owners of original cars who can confirm if this clip was installed on Z28's sometime after the start of the '69 model year launch, or at all during that model year.


Can anyone provide some insight on this?  Thanks.

Setting up this donation route was an excellent move!


Here's a thought:  Like many of us have, I just recently had some automotive related parts I no longer needed listed for sale on Marketplace and/or Craigslist.  I was prepared to accept a modestly lower offer price for my items but the purchaser was so pleased with what I had for sale, he gave me my asking price -- so I donated the difference to the CRG.  A win/win if there ever was one!