[War eagle]

Well then lets get ol Toms trips linkage up here. Shouldn`t this have been 10 years ago? That extension as previous stated, would really be a problem solver.

[John V.]

pfilean, oops, my bad. I told you I was no expert on this!

I believe you are correct, the heavier/stiffer springs were for the Vac Secondaries to help close the end carbs when you got off the gas and before the Vac could bleed off. The replacement Springs would have been lighter/weaker, not the reverse. It is debatable whether the kit Packages included these springs although we know the '65 factory set-up used the lighter springs with the Mech Linkage, pretty sure they knew they should be used with the '64 kit Packages also.

Based on the existence of the obviously related p/n for the shaft & lever, I think at the very least the entire shaft & lever came in the kit Package and quite possibly an entire Throttle Body Assembly simply because it would have been tricky to set up the Vac Throttle Body with a replacement shaft. I very much doubt that they would have only included the lever itself.

Hopefully Tom will get here soon or I'll try to raise him by email.

[Dick Boneske]

The factory Tripower vacuum linkage setup used stiff return springs on the end carbs--for all years and models. Most mechanical linkage kits, Pontiac factory included, supplied weaker return springs for the two end carbs. I supply these with my kits and have them available separately if you need a pair.

The stiffer springs require undue accelerator pedal effort and wear and tear on the throttle linkage components. I have never had a problem with end carbs sticking open with the weaker springs. Remember, the accelerator pump well spring also helps close the throttle.

As stated in the last posting, the rear carb shaft was included in the factory mechanical linkage kit because the rear carb had no usable throttle lever--only a stubby one to operate the accelerator pump. The factory kits had the larger lever already swedged to the throttle shaft so the installer only had to remove the stock throttle shaft and install the new one. The trickiest part would have been removing and replacing the throttle plates--removing the swedged 6-32 brass screws and getting the plates positioned to seal properly.

[60sstuff]

Interesting pic showing the difference in size between the big spring for the vacuum set-ups and the small spring used with the mechanical linkage.

[Tom Vaught]

Originally Posted by John V.

Dick, yes, this is the '64 Mechanical Linkage Package. It included several parts.

1) I am not an expert on this but have studied the parts and p/ns a bit.

2) You mentioned the "triangular" piece.

3) Early mag articles showed this set-up. I believe either the '64 Kits were not yet released (most likely, IMO), or Dealers like Royal were used to working with the older Kits and simply installed them on the test cars rather than acquire the "correct" Dealer Accessory Package.

4) The GTO Package was p/n 9777060, the big car Package was p/n 9777061.

5) Presumably all of the parts to make the conversion were contained in each kit Package.

6) This included the Center Carb Lever Extension, for the GTO p/n 9777063 and for the big car p/n 9777064.

7) Since the big car used a different style lever extension, I will continue for the GTO only.

8) There was the Throttle Control Cable Mounting Bracket p/n 9777062 which was specific to the '64 GTO Mechanical Linkage kit Package.

9) As to your question about securing this throttle lever extension to the Center Carb Throttle Lever itself, I'm not real sure how it was to be done. I agree with what you described for the lower attachment, the regular 1/4"-28x1/2" hex bolt and nut secured it, same as for the factory lever extension.

10) At the top, a stud may have been used. This may be the stud described in the MPC (Gr. 3.425) as the '64 Throttle Control Cable To Carb. Lever w/ Mechanical Linkage, p/n 9777067. Based on the p/n, it was undoubtedly part of the kit Package.

But nothing I've seen indicates that there was any upper attachment of the Lever Extension to the Throttle Lever. The pic I posted shows the raised circle on the Lever still intact.

How was the regular T-P Lever Extension attached, were there 2 attachment points on it?

11) The last identified component is the Throttle Shaft & Lever p/n 9777065 for the Rear Carb. It is listed in Gr. 3.463. I do not remember why this part needed to be replaced to facilitate the Mech Linkage, I think it was to get the specific Lever, swedged to it. I assume the Throttle Shaft Return Springs were also changed for the heavier ones but that would not have required the removal of the Throttle Shaft. IIRC, Tom Vaught's Rear Carb features this Throttle Shaft and the heavier springs.

12) The p/ns assigned to the kit Packages and the associated parts (977706*) is why I believe these parts were released relatively late in the year. Chronologically, they were issued after certain other parts that did not appear until late, such as the '64 M21 trans which was p/n 9777000.

My own guess is that they were not available at the Dealerships until about April, '64. Any earlier conversions would have been aftermarket stuff or cobbling together from the earlier Mech Linkage Kits such as was seen in some of the mag articles about the '64 GTO.

GREAT DISCUSSION SO FAR.

I will attempt to answer some of the question posted and clarify a couple of items posted so far. I have numbered John's Post.

1) Still know a lot more that most

2) Agree, Triangular Piece was used on the 1961 Tri-Power Super Duty Mechanical Linkage. I also have a print of this Linkage and the FOUR different settings that you can set the linkage at for Opening Point and Opening Rate.

3) Dealers simply ordered the 1961 SD parts.

4) Agree

5) I rebuilt a guys Vacuum Tri-Power set-up one time and as part of the parts he shipped to me (that he bought from dealers over the years was a complete system of parts. It did not have the "stud" you mentioned in the kit.

6) Agree

7) Disagree somewhat. The "Big Car" Extension p/n 9777064 is IDENTICAL is shape and manufacture EXCEPT that the return spring portion of the extension was removed (cut off and saw cut smoothed before plating) as the Big Car used a solid rod/ bracket mounted return spring assembly vs the GTO's Throttle Cable system.

8) Agree It is NOT a welded piece.

9) Agree

10) You are very close John. The Raised detent in the normal Carb lever is used to REGISTER the upper hole in the Kit Carb Extension. A Stud and SPACER goes THRU the farthest most forward (raised) portion of the carb extension and mounts in the THIRD hole down. The top two holes are for the 4 different settings you can use with the linkage (just like the 61 linkage). The Rear Carb Lever ALSO has two holes vs one to allow the 4 settings.

11) The Rear Lever swedged to the rear carb shaft, as mentioned in "10" has the 2 holes so the lever IS different from the 1965-65 type linkage. With the 65/66 type linkage you have quite a bit of adjustment on when the rear carb starts to open and if you want the rear carb to open all of the way. With the 61-64 type linkage the tube and plunger had very little adjustment without the plunger coming out of the tube so they designed the adjustments in the 4 lever arm holes.

As I mentioned before my car came with this Mechanical Linkage from the Pontiac Zone Office along with a whole bunch of other changes (including a wood dash insert). I have mentioned that my rear base has the 2 hole lever, is a 1964 base casting, and the blade screws are swedged by Rochester Products. I have intentionally left out one item for the Nay Sayers over the years. My Rear Lever Arm has a RP "Job Number" stamped on the swedged Rear Arm. The Set-up WAS built by Rochester products, Installed on the car before I received it (along with the other mods and eventually I received it. It was not a dealer installation.

12) Agree that the parts were issued after April 1964.

One other item that is very important. Some factory press pictures show the mechanical linkage (Tube and Plunger parts) installed on 1965-66 vehicles. The Tube goes on the rear carb. If the tube is installed on the center carb (as shown in Doug's picture the plunger can fall out and wedge on the heat cross-over locking the rear carbs open. BAD DEAL.

Doug's home built set-up has a 1 to 1 lever ratio (arms the same length) so his set-up will not have that issue. Factory the ratio is about 2 to 1 for the length of the center lever distance vs the rear lever distance to the shaft center.

Tom Vaught

So to be correct Dick, you need to make a stud and spacer that mount in the third hole vs grinding off and drilling the top hole.

[John V.]

Tom, thanks for explaining the difference between the big car & GTO Lever Extensions, that is new info for me.

I'm surprised that the complete kit Package that you received did not have the p/n 9777067 Stud? Or maybe I confused the issue by my weak explanation?

The Stud in question would have been the one that you describe (along with a Spacer) as installing in the 3rd hole down on the farthest forward portion of the Lever Extension. Was THAT Stud & Spacer included in the kit Package?

I also have not mentioned the Plunger & Rod. I assume these were also included in the '64 kit Packages and were the SAME Plunger & Rod pieces used in the earlier Mechanical Linkage Packages. Listed in Gr. 3.430, p/n 529814 for the Front Secondary Throttle Control and p/n 529815 for the Rear Secondary Throttle Control.

Dick or Tom, based on you having seen the actual Packages, did the package contain the p/n 9777065 Rear Carb Throttle Shaft & Lever or a complete Throttle Body Assembly?

Mag articles of the period mentioned having to install the replacement Throttle Shaft & Lever that came with the kits but these are somewhat ambiguous because the conversion were conducted on big cars using the earlier kits with the triangular Lever Extension.

I have never seen an NOS '64 Package to know what was in it, just guessing from the p/ns. If they supplied it like the earlier Kits, only the Throttle Shaft & Lever was supplied.

Tom, given what you know about your car and the appearance of your Rear Carb Throttle Body, it is conceivable that your car was converted by PMD using "prototype" pieces, in this case, a complete Throttle Body or maybe even a complete Rear Carb to swap out the original while the "production" Dealer Kits may have been supplied with the substitute Throttle Shaft & Lever only.

Only real point of interest here is whether p/n 9777061 included a complete Throttle Body or just the Shaft & Lever. The net result was the same as far as the functionality was concerned.

Don't know if it is worth posting these, I have converted them to jpeg so I could post them and the quality is poor. Got these from a fellow hobbyists a few years ago, he and I were researching the Vac system for the most part, the Mech Linkage stuff arose out of that.

The first is the Instruction Sheet for install of the early Kit, might be the same sheet Tom refers to.

The other is from a publication called Speed Mechanic, only have this page. It shows a GTO with the "correct" kit Package installed although they don't discuss details of the install and the pic is probably too fuzzy to make much use of it. Some may note the throttle return spring. It is unknown if the kit Package included a specific spring here or perhaps the tester installed a different spring in an attempt to get a better pedal response?

No definitive stuff here except to show that the '64 Mechanical Linkage kit stuff did exist during the '64 Model Year and while it may not be found in the '64 MPC, Dealers apparently were made aware of it in some fashion.

[John V.]

Most of you already know you can't trust "evidence" from mag articles, whether in a new mag today or one from 50 years ago.

As proof of that, consider the 2 small photos on the page I posted.

The first caption says the GTO was ordered with "heavy duty suspension, including special front springs, heavier stabilizer bar, and a faster steering ratio". This is all bogus, there really was no such option.

What you COULD order was the Heavy Duty Springs & Shocks, Sales Code 621. That normally included the Delco heavy duty shocks and specific stiffer springs in a Tempest.

But with the GTO, there wasn't any specific springs available as an option, so this option ONLY included the Delco heavy duty shocks when ordered with the GTO option.

You could also order the Rally Handling Kit, Sales Code 612. This normally included the same Springs & Shocks as included in the Sales Code 621 option and added the thicker 15/16" dia. front stabilizer bar and the quick ratio Manual Steering Box.

But the standard stabilizer bar in the GTO was the 15/16" bar, so once again, with the GTO option, Sales Code 612 only added the Delco heavy duty shocks and the quick ratio Manual Steering Box, nothing else.

The 2nd pic then shows the engine bay, equipped with the Power Steering Box! If it is the same car as tested, it could NOT have been ordered with the quick ratio Manual Steering Box, so the caption for the 1st pic would be totally bogus. Most likely the test car was PS equipped with heavy duty shocks and that was it as far as "heavy duty suspension" vs. any other GTO was concerned.

Just want to make the point that you can't look at old mag articles and expect to see or read "proof" of how things were done without taking it with a grain of salt.

[pfilean]

Hope this doesn't get to far off subject as the discussion is primarily 1964. But attached are two pictures from a 1965 sales brochure. As you can tell from the captions one picture is suppposed to be GTO the the other big car as referenced by HP and CI. But I can't say they didn't use the same engine for both pictures. As John V. points out you can't always trust the press/advertising people.

But notice that the tube is on the center carb not the rear as per the post from Tom Vaught. Maybe the factory learned their lesson after these pictures were taken and they had stuffed a test car against a track retaining wall.

[Dick Boneske]

Now, I'm really confused. I have never seen (or maybe never noticed) the '65 "J" arm with no hole in the top portion to secure it to the center carb throttle lever. I've rebuilt/restored many '65 setups that appeared to be unmolested (at least as far as parts replacement goes), and they all have a hole to accept the throttle cable stud(GTO) or throttle rod ball stud (big car). These pictures both have the GTO throttle cable tower with NO THROTTLE CABLE--and no place to attach the cable. Interesting!!?

One more point. The '65 GTO used a longer throttle cable stud attached to the "J" extension and throttle lever than the '64 GTO replacement linkage. I have attached pictures of both studs--originals, not repros. The '64 stud is 1 3/8" OAL, the '65 is 1 7/8" OAL.

Sure would like a picture or dimensions of the stud used with this "other" carb lever extension with the spacer or whatever was used to attach the extension to the carb lever.

[60sstuff]

Originally Posted by pfilean

But notice that the tube is on the center carb not the rear as per the post from Tom Vaught. Maybe the factory learned their lesson after these pictures were taken and they had stuffed a test car against a track retaining wall.

That wall crash must have really freaked them out cause they even removed the throttle cable.

[Tom Vaught]

Some 1964 Mechanical Linkage Component Dimensions

Big Car First,
We have the following parts:

Rear Tube: Diameter is .500" steel material (Silver Cad Plated).
Length is 2.883" long (.500" Diameter length is 2.100" long)
"Ball End" reduced length is .700"
"Ball Hole" is designed to use a .250" ball stud
"Ball Stud Length is 1.125" long
"Hex" to tighten Stud is .312" on the flats
Opening of Tube has slight radius on both the ID and the OD of the Tube
Tube is Cad Silver Plated (I assume)

Rear Lever: The Rear Lever I have access to does not have a shaft swedged onto it.
Material is steel (Silver Cad Plated)
Material Thickness is .127"
Lever has 2 holes (Hole diameter is .250")
Center of shaft to 1st hole is 1.860"
Center of shaft to 2nd hole is 2.160"

Center Lever:
Material is steel (Silver Cad Plated)
Material Thickness is .124"
Spring Extension Arm has been removed
Lever has 2 Holes at top most of Lever for Linkage Adjustments

Center Extension Lever Mounting Stud/ Bolt/Nuts

This is for You Dick, Merry Christmas

Upper Lever Extension Mounting Ball Stud is Cad Plated
Total Upper Lever Extension Mounting Ball Stud Length is 1.936" long
Ball Stud has .312" Hex (.200 tall) on outside of lever
Ball Stud Length (of round shank to tip of ball) .880"
Length from Hex to end of thread/stud .880" Long
Area after Hex but before Threads is .120" (same as extension thickness)

Lever Extension Mounting Ball Stud is Cad Plated
Lower Mounting Ball Stud is 1.810" long (Threads are .510" long)

Plunger Dimensions and Info

Plunger is Cad Plated
Plunger is made of three specific parts:
Internal Threaded Hex/Ball Socket Portion
Plunger "Length Adjustment" Lock Nut
Threaded Plunger (with Hex Portion and smooth portion)

Combined Threaded/Smooth Plunger Length is 4.110"
Plunger has 1.385" of Thread Length/Adjustment
Plunger has 2.210" of "Smooth" Length
Plunger has .435" of Hex Length
Smooth Plunger Diameter is .248"
Hex/ Ball Socket Length is 2.584" long
Hex Portion is 1.233" long


Tube Dimensions and Info

Tube is Cad Plated
Tube is 1.887" long
Tube Inside Diameter is .288"
Tube has radiused inlet hole and rounded end face


The Tube and Plunger parts ARE available and are not necessarily made exactly the same

The 1964 Extension Arm is Not reproduced

The Ball Stud parts are common but possibly different lengths

The Big Car Ball Pivot Upper Mounting Stud is Extremely Rare. You can possibly have them repoped now that you have the dimensions.


Tom Vaught

ps My Rochester 64 GTO Throttle Cable Stud may not represent the Production part but here are the dimensions:

Length is 2.136"

Hex Portion is .870" long

Cotter Pin portion is .400" long

The Hex Spacer is is made from .312" steel Hex material and is, as mentioned above .312" long.

The Hex Spacer fits over the threaded portion of the Stud.

The Hex Stud Thread is .750" long

My Rear Lever is Swedged On the shaft and is also Rochester Products peened at the Throttle screws
The Lever has a RP Stamp and Job #

[Tom Vaught]

Originally Posted by pfilean

Hope this doesn't get to far off subject as the discussion is primarily 1964. But attached are two pictures from a 1965 sales brochure. As you can tell from the captions one picture is suppposed to be GTO the the other big car as referenced by HP and CI. But I can't say they didn't use the same engine for both pictures. As John V. points out you can't always trust the press/advertising people.

But notice that the tube is on the center carb not the rear as per the post from Tom Vaught. Maybe the factory learned their lesson after these pictures were taken and they had stuffed a test car against a track retaining wall.

I saw the picture on the left in 1965 and swapped my Tube and Plunger linkage around. THEN the Plunger came out of the Tube!!!!!!!!!!!!!!!!!!!!!!! Not Good.

Tom vaught

[pfilean]

Tom
Hope that you learned without the crash I suggested for the factory.

[Tom Vaught]

I had driven long enough (since 12) that I turned the key off with my left hand, kicked in the clutch, and coasted to a stop. Drove home with no mechanical linkage on the car.

If you look at how well engineered the 1965 Mechanical "Pin and Slot" Linkage is, you have to believe that at some point GM had some bad experiences with one or more cars on the test track or on the street with the Tube and Plunger linkage.
"Engineers Do Stuff for a Reason".

Tom Vaught

ps The Heavy Springs were very hard, as was mentioned in the article, on the Tri-Power linkage. Have repaired a couple of units where people broke the lever right off the center carb when the swedge finally gave up. Course I have seen that deal too on some Holley road-race carbs. Reason why race carbs have welded steel shafts/levers.

[Dick Boneske]

I never had the rod & tube backwards to cause a jamb, but will never forget my first experience with vacuum linkage on a three carb setup.

In 1963, when I was 21 year old, I bolted a J-2 setup on my '57 Olds Super 88 Rocket in place of the Rochester 4 bbl.! The first test drive was on a busy main street near where I lived in Wauwatosa--North Avenue. I waited for clearance ahead of me, punched it, marveled at the power, waited until I was approaching a car in front of me, backed off!! It takes a fraction of a second for the end carbs to close with vacuum linkage!!! That seems like forever when you're approaching a 25 mph car when you're going 65!! I didn't hit him, but he heard the tires squealing when I locked up the brakes--probably had to change his underwear as I nearly did!!

Just a story from "back in the day!"

[John V.]

War Eagle, I was just going back over this thread.

In Post 18, you mention that no Kit was listed in Gr. 3.454 in the late revised '64 MPC.

I have been told before that the Kits were not listed in the '64 MPC which I don't doubt.

But in the '66 MPC they are listed in Gr. 3.429.

Could you do me a favor and check this Group just in case they really WERE included?

Thanks.

[60sstuff]

The above on line site which is owned by Colin Comer shows numerous pics of a 64 GTO that is claimed to be a complete factory original 20,000 mile car. It has this mechanical linkage on it which I show a pic of in my previous post. Now I am unable to right click and copy to enlarge any of his pics, but if someone is close to Milwaukee, WI. they can go over to his shop and have a close look at this "time capsule" and maybe take some detail pics. I would be curious if Colin got any paperwork on the linkage swap and if it still has the big vacuum return springs and the vacuum reserve tank tucked in the RH inner fender?? Anybody close to his auto showroom?

[Dick Boneske]

I'm 80 miles north of Milwaukee and get there occasionally. In fact, next week I have to go to Slinger, which is not far from Milwaukee, to get some carbs colored.

Is there any chance I could look at the car and take some pictures and inquire about paperwork pertaining to the Tripower? Also, I belong to the Badger Chapter of POCI which has quite a few members in Milwaukee. I will inquire if any of them know Colin and could enhance a visit to the shop as you suggested.

[60sstuff]

"Colins classic automobiles" Great site and I think it has hours posted for visiting his showroom. He seems to favor original survivor cars (not restored), especially the early GTO's so there should be some valuable references to be seen in his collection. If I was within several hundred miles I would make time to see all his cars!

[John V.]

Since Colin Comer's '64 GTO has the Mechanical Linkage, "factory original" wouldn't apply to the linkage.

I emailed Colin back in April about the trans in the car. I explained that I was continuing to search for '64s that were factory built with the close ratio trans.

Tenney Fairchild made me aware of Colin's car, I noted that he claimed it to have the close ratio.

At the same time, I had become aware of the 8000 mile '64 GTO that also was thought to have the close ratio.

Both cars were built with the 3.90 axle.

In a thread here, it was confirmed that the original trans in the 8000 mile GTO was the code 9 WIDE ratio as I expected.

Colin was traveling when I first contacted him, he replied that he would check the trans p/n tag on his return. I'm 99% sure it will prove to be the code 9 wide ratio and not the extremely rare code 8 close ratio.

I replied with some additional info for him but never heard from him again.

I would still be interested in confirming that his GTO has the original code 9 wide ratio trans by p/n if anybody does get in contact with him.

IIRC, the 8000 mile GTO still has the original factory Vac set-up which makes it a bit more interesting in my view, despite the "driveability" flaws.

Complete "correct" '64 Mechanical Linkage setups are also fascinating and I wish I had a complete kit myself.

War Eagle, did you see my request to check Gr. 3.429 in the '64 MPC revision?