#21  
Old 12-10-2021, 02:40 PM
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Quote:
Originally Posted by carbking View Post

If the car is showed at a points judging show, the car will lose points with the wrong carb UNLESS you can find the build sheet. Being the original owner will not help.

Jon
I have a Firebird Formula that came from the factory with a Formula 350 fender emblem on one side and a Formula 455 on the other. Was always an interesting conversation with my father-in-law who was into judged, restored antique cars.

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  #22  
Old 12-10-2021, 02:50 PM
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A bit more information on the single ring Q-Jets:

First, 7041263, 7041267, 7041268, 7041270 and 7041273 were single ring.

Somewhere (don't ask where, I don't know, and too much stuff to go through) I have a Pontiac flow test on the single ring carbs. It was approximately 825.

The idea came from Carter. Many know that Carter produced literally millions of Q-Jets under license from GM. Thus, the Rochester engineers worked closely with the Carter engineers. In 1969, Carter introduced the Competition Thermo-Quad spread-bore carburetor in 850 and 1000 CFM ratings for RACING ONLY. There was approximately 100 CFM difference in the primary side of the double ring 4846 (850 CFM) and the single ring 4847 (1000 CFM). The secondary side was modified to gain the extra 50.

The Pontiac engineers saw what Carter was doing, and had Rochester try out the single ring in 1971.

I have no written documentation on this, but I have been told the reason for discontinuance of the single ring carb had to do with emissions calibration, not performance.

The Carter single rings DID have idle issues, but the primary side of the Carter was approximately 100 CFM larger than the primary side of the single booster Rochester. We have sold a few of the 1000 CFM to folks with some of the BIG (500 + CID) engines, who tell me they will idle on the big engines.

Carter later "detuned" the Thermo-Quad for street use in both 800 and 850 CFM ratings, but used two different size of primary venturii rather than using the single ring. ALL of the Carter street TQ's were double ring.

As to "one-off" engines or carburetor changes, NOT AFTER FEDERAL SMOG EMISSION WENT INTO EFFECT FOR THE 1968 MODEL YEAR. Big brother was VERY SERIOUS about compliance! And they didn't carry a big stick, they carried a big tree!

Jon.

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Last edited by carbking; 12-10-2021 at 02:58 PM.
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  #23  
Old 12-10-2021, 02:56 PM
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Quote:
Originally Posted by PAUL K View Post
I have a Firebird Formula that came from the factory with a Formula 350 fender emblem on one side and a Formula 455 on the other. Was always an interesting conversation with my father-in-law who was into judged, restored antique cars.
Mistakes happen, but a judging authority must have standards to go by.

Also, sometimes the printed documentation is wrong. A good carburetor example is the special carb (that did NOT go into production) for the 1970 RA 455 engines.

Jon.

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"Good carburetion is fuelish hot air".

"The most expensive carburetor is the wrong one given to you by your neighbor".

If you truly believe that "one size fits all" try walking a mile in your spouse's shoes!

Owner of The Carburetor Shop, LLC (of Missouri).

Current caretaker of the remains of Stromberg Caburetor, and custodian of the existing Carter and Kingston carburetor drawings.
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Old 12-10-2021, 03:15 PM
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Quote:
Originally Posted by PAUL K View Post
Can you tell us the carb numbers for a d-port 71 455 four speed application?

I thought I've seen 267 and 273 on HO455's
1971 STD 455 with M/T (and 400 with M/T) uses the 7041263.
HO uses 267.
RamAir uses 273.
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Old 12-10-2021, 04:39 PM
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Quote:
Originally Posted by carbking View Post
Very interesting thread. Really wish you had the build sheet, which is going to be the definitive document for this case.

Just for grins, checked the following:

Pontiac power train charts for 1971 show the 263 carb for manual transmission 400's and 455's other than the H.O. which got the 267 and the Ram Air which got the 273.

Rochester Master Products book concurs with the above.

Pontiac service bulletins from 1971 through 1976 do not show any change from a 263 to a 264 for 1971.

Would GUESS this was an error at the factory.

Pontiac would have been subject to a massive fine for arbitrarily changing emission certification standards.

The cars with the single booster AND manual transmissions WOULD idle. It was the cars with auto transmissions that had idle issues with single booster carbs.

Going forward (opinion):

The 7041263 in stock calibration will deliver SLIGHTLY better (5 percent???) fuel economy around town.

If the car is showed at a points judging show, the car will lose points with the wrong carb UNLESS you can find the build sheet. Being the original owner will not help.

Jon
Thank you VERY much for speaking up Jon!

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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)
  #26  
Old 12-10-2021, 05:36 PM
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Well, out of sheer curiosity, I placed an order for the PHS documentation on my car…maybe it will shed some light on what happened between the dealer order and factory build. If the dealer made a mistake and ordered the M22 (code 35G) instead of the M20 (code 35E) and it triggered the automatic inclusion of the other two options, then it should be apparent in the paperwork from PHS.

Not sure if I will receive any documentation identifying which carburetor was installed. Maybe in their haste to make up for lost production because of the 2-month UAW strike in late 1970, the wrong carb was installed inadvertently and nobody noticed. My car also has tail light lenses without the ribs, which I believe were used on the ’70-’71 Tempest and base LeMans…maybe a case of using whatever they had on-hand to “move the iron”.

I’ve also attached my original purchase agreement and invoice which shows that the M22, HD Posi, and HD radiator were not included in my order…and the dealer also absorbed the additional cost, since I only paid for what I ordered (the price adder for the three items was a whopping $84.36). Another point of interest is that I also received a discount off the sticker price of $442.65 which was buried in the Used Car Allowance of $1092.65, since they gave me $650 for my ’66 Chevelle as a trade-in.
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Old 12-10-2021, 06:26 PM
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I just noticed that there is a small note at the bottom of the 1972 brochure that reads "with dual exhaust 250hp @ 4400 (H.P.)" & "with dual exhaust 325 @ 3200 (Torque)" - this probably was there to differentiate the 400/4bbl engines that the full sized cars got from the ones the GTO's, GT-37's, & Firebird Formula's received.

With that, I'm correcting my earlier post:

Finding published 1972 hp ratings is a tricky thing though, I have only found them in the 1972 GM of Canada brochures.
With the same cams, pistons, and cylinder head combustion chamber designs, I believe that the slight difference in hp ratings is the revealer here;
1971 455-HO: 310 HP(net)
1972 455-HO: 300 HP(net); -10 HP
1971 455/4bbl: 260 HP(net)
1972 455/4bbl: 250 HP(net); -10 HP
1971 400/4bbl: 255 HP(net)
1972 400/4bbl: 250 HP(net); -5 HP

LINK

I also feel like a bit of an idiot for typing some of my replies as though you had a Firebird Formula - sorry!

I wanted to touch on this:

Quote:
Originally Posted by Stan R View Post
... the factory also decided to upgrade my car with ... and a heavy-duty limited slip differential with 3.90 gears, none of which I had originally ordered. ...
Your hand written order from the dealership includes "Safe-T-Track" as the second item, so that's one less "freebie".

Thanks for sharing those pictures!

Any pictures (past or present) of your car you might care to share?

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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)
  #28  
Old 12-10-2021, 07:40 PM
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I should probably clarify the factory upgrades to make it a little clearer:

Ordered at the Dealer:
M20 Muncie 4-Speed - $195.36
Safe-T-Track (Std) - $46.34

Received from the Factory:
M22 Muncie 4-Speed - $237.60
Safe-T-Track (HD) - $67.40
Radiator-Heavy Duty - $21.06

I’ve attached current photos of the Goat as well as a reproduction window sticker that lists all options that the car now has, including others I couldn’t afford as a 19-year-old kid that were added later in order to fend off a mid-life crisis. I’m proud to say that everything on the car is a legitimate option that was available in 1971, including the body accent stripes, which I personally have never seen on another A-Body.
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Old 12-11-2021, 05:18 AM
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Wouldn´t the 1971 WT7 option indicate a white car with black spoiler and stripes?
Not on a regular GTO i guess.

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Old 12-11-2021, 11:37 AM
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Quote:
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Wouldn´t the 1971 WT7 option indicate a white car with black spoiler and stripes?
Not on a regular GTO i guess.
I immediately spotted a couple errors on tha, so I'd wager that sheet is full of errors.

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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)
  #31  
Old 12-11-2021, 11:39 AM
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See attached page from the 1971 Pontiac Accessories Catalog. The WT7 option (Rear Deck Airfoil) was dealer installed and consisted of only the airfoil without any reference to car color or striping. It was available on the T-37, LeMans, and GTO.

I bought an NOS airfoil many years ago from a POCI member and painted and installed it myself. Locating it on the deck lid was kinda tricky cuz there were threaded mounting studs that stuck out on the support stanchions that were fixed and couldn’t be removed. This prevented me from just being able to set it on the deck lid to get a good visual of where it needed to be mounted before drilling the holes. I basically studied pictures of ’71 Judges and developed some location dimensions by scaling distances on the pictures. I used the same technique on the hood tach as well because of the fixed mounting studs on the bottom of the tach.
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  #32  
Old 12-11-2021, 11:42 AM
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Nice car.

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Old 12-11-2021, 12:07 PM
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Originally Posted by unruhjonny View Post
I immediately spotted a couple errors on tha, so I'd wager that sheet is full of errors.
If you don't mind, could you please be more specific and list the errors that you you found?

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Old 12-11-2021, 12:44 PM
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Quote:
Originally Posted by Kenth View Post
All 1971 400 and 455 4 bbl engines (except H.O. or RamAir) with M/T uses the one year only single booster 7041263 Quadrajet.
If memory serves, A & F Bodies with 455 D-port engines (325 hp) were TH400 only, manual trans. not available (except in the very early for B-body...weird).

Dennis

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Old 12-11-2021, 01:02 PM
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Quote:
Originally Posted by SD455DJ View Post
If memory serves, A & F Bodies with 455 D-port engines (325 hp) were TH400 only, manual trans. not available (except in the very early for B-body...weird).

Dennis
I believe that you're correct. See attached spec sheet from 1971 Pontiac sales brochure. This chart was taken from the GTO page, but I checked all of the other vehicles including Full-size, Grand Prix, Firebird and LeMans and they all showed that the only trans available for the 325 HP 455 was the Turbo Hydra-matic.
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  #36  
Old 12-11-2021, 05:27 PM
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I've got a bunch of good photos of an NOS 264 that I went through not long ago if you need any.

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Old 12-11-2021, 05:44 PM
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Quote:
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If you don't mind, could you please be more specific and list the errors that you you found?
1970 Lemans Sport & GTO order sheet

Your 'as-is' window sticker reads:
M22 4 SPD CLOSE RATIO TRANSMISSION 35E
G80 SAFE-T-TRACK DIFFERENTIAL-HD 361

I would guess that (option wording aside) it should probably read:
M22 4 SPD CLOSE RATIO TRANSMISSION 35G
G90 SAFE-T-TRACK DIFFERENTIAL-HD 368

35E was the M20
361 was the standard safe-t-track
That option sheet makes it look like option code 368 should be either G90 (3.90?) or G92 (4.33?).

Those two jumped right out at me;
(Please see linked order for as to why I am suggesting the different codes)
I am not sure on correct wording for any given option, as an example would need to be seen to pattern it after.

Quote:
Originally Posted by SD455DJ View Post
If memory serves, A & F Bodies with 455 D-port engines (325 hp) were TH400 only, manual trans. not available (except in the very early for B-body...weird).

Dennis
I was thinking it, but not being an expert on the Tempest/Lemans/GTO, I kept my thoughts to myself.
I know that the 455 D-port engine on the Firebird was TH400 only, and assumed the same for the GTO (ect).

But, I really came here just now because I just noticed something with a different piece of period literature(!);
I took your "3.90 gear" comment with a grain of salt, and did that because I know it was offered before 1970, but not being anything of an expert on GTO's or post-1970 Pontiac optional equipment, I assumed you were mistaken on that gear ratio;
I had understood that the GTO still could get the Pontiac rear end in 1970, but didn't know if it was available after that;
I knew that GM was going corporate in 1970 and that it wasn't too unusual to see a corporate 10 bolt under a Lemans, and that if oped right a corporate 12 bolt could be found in a GTO;
I had understood that 3.90 (& 4.33) was a gear ratio not offered with corporate differentials - but rather 3.42 (10 bolt), 3.55 (12 bolt), and 3.73 (10 & 12 bolt) was.

What I was previously looking at was 1972 literature, and the 1971 'Performance catalogue' - the latter doesn't give any indication of optional gearing...

Except(!)

I just noticed that in the deluxe full line catalogue, the full optional differential gear sets are clearly spelt out in the Lemans, T-37/GT-37, and GTO powertrain charts!

That's just too cool!!

It seems to be quite clear that the 3.90:1 gear set was standard when the "4-speed (close ratio)" transmission (aka: M22) was ordered;
And it also shows that it was optional with the standard 3-speed (HD-Muncie) transmission!!
Which in turn means I need to now look up a 1971 GTO speedo gear chart, to confirm was was used for the Muncie three speed w/3.90 gear set;
I had previously planned on winging it based on my own calculations - this is what I intend to run in my car - I already have a spare differential and everything to set it up!
(I hope that I find that gear set to be quite liveable, my Grand Am has 3.94:1 gears (swapped in from 3.61:1), my Cobalt has 3.82:1 gears, and my truck has 3.73:1 gears -granted all of these have overdrive, but I will leave the cars in fourth sometimes just because...)

The more I learn about 70-72 GTO's, the cooler they are to me.

I have always liked GTO's, they always seemed the Firebird's bigger brother - and even though things currently seem to have somewhat reversed, when I got my Formula 400 (in 1995) a similar equipped same-year GTO would have probably had at least a 50% higher asking price - if not double.

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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)

Last edited by unruhjonny; 12-11-2021 at 05:50 PM.
  #38  
Old 12-11-2021, 07:47 PM
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The 8.2" 10-bolt 3.90/4.33 was indeed available as options in GTO's from the factory in 1970 with the same transmissions with mandatory HD radiator and speedo adaptor. It's my understanding that in 1971 any 2-dr A-body with a 400 4-bbl could be factory ordered with the 3.90 rear gear with either the HD M-13 3-speed, close ratio M-21/22 4-speed, or the TH400 in the 8.2" 10-bolt rear end with the mandatory HD radiator and speedo adaptor, while the 4.33 was only dealer installed. 1972 A-bodies used the same rear ends as '71, however, I believe the 8.2" 10-bolt 3.90/4.33 gears were dealer installed only...not available from the factory as options.

The 8.5" 'corporate' 10-bolt rear end only came in the F-body line -up in 1971/72, then in the 1973-up A-bodies. Pontiac and Chevrolet continued on with their own versions of the 10 and 12 bolt rears for 1971/72, while Buick and Olds went to the 'corporate' 8.5" 10-bolt for '71/72.

Dennis

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Old 12-11-2021, 08:27 PM
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/\ thanks for sharing that!!

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1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)
  #40  
Old 12-11-2021, 09:19 PM
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Quote:
Originally Posted by Stan R View Post
Well, out of sheer curiosity, I placed an order for the PHS documentation on my car…maybe it will shed some light on what happened between the dealer order and factory build. If the dealer made a mistake and ordered the M22 (code 35G) instead of the M20 (code 35E) and it triggered the automatic inclusion of the other two options, then it should be apparent in the paperwork from PHS.

Not sure if I will receive any documentation identifying which carburetor was installed. Maybe in their haste to make up for lost production because of the 2-month UAW strike in late 1970, the wrong carb was installed inadvertently and nobody noticed. My car also has tail light lenses without the ribs, which I believe were used on the ’70-’71 Tempest and base LeMans…maybe a case of using whatever they had on-hand to “move the iron”.

I’ve also attached my original purchase agreement and invoice which shows that the M22, HD Posi, and HD radiator were not included in my order…and the dealer also absorbed the additional cost, since I only paid for what I ordered (the price adder for the three items was a whopping $84.36). Another point of interest is that I also received a discount off the sticker price of $442.65 which was buried in the Used Car Allowance of $1092.65, since they gave me $650 for my ’66 Chevelle as a trade-in.
Cool….. shared my original invoice for comparison.

Mine is a 400 auto car and came with the 7041264 carb. Played around with many qjets including single ring 263’s…. They ALL generally perform the same IF setup properly for your application. The 264 is a decent carb but I prefer the mid to later 70’s carbs for Perfomace builds.
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