Robert G. Smits

66 GTO; Change Rear End Ratio vs Overdrive

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The correct pejorative was "Garbage Truck Option". And don't forget "put a tiger in your tank" (the loop attached to the gas cap).

tigertail.jpg

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19 minutes ago, padgett said:

 (the loop attached to the gas cap).

tigertail.jpg

 

Did it now??? That would be tail dragging.

Image result for image of long Pontiac Tiger tailsImage result for image of long Pontiac Tiger tails

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43 minutes ago, alsancle said:

You learn something new everyday.   My HS days were 78-82  and Goat was never used a a pejorative.    The Tiger thing did not seem to stick.

Ah, The young ...so sad. Pontiac advertising did their best;

 

 

 
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In 1970 or so ESSO had a promotion " Put a tiger in your tank " to promote their gasoline. They handed out tiger tails to hang out  of your gas tank.

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20 minutes ago, misterc9 said:

In 1970 or so ESSO had a promotion " Put a tiger in your tank " to promote their gasoline. They handed out tiger tails to hang out  of your gas tank.

They bought all the leftovers for when G.M.'s President made Pontiac give up the Tiger theme after 1966, They also made Pontiac give up it's Tri-power, a symbol of Pontiac power that Pontiac had used since 1957.

Pontiac's new GTO theme for 1967...……"THE GREAT ONE" 

Edited by Pfeil (see edit history)

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Well sorta. Rochester was pushing the QuadraJet as the answer to everything. Originally 750cfm later there was an 800cfm variant with larger primaries.. And the tiny primarys and metering rods gave a lot better mpg than the 2GC (center carb) of the tripower. Besides the "small center" (pre-1966) was only about 170 cfm while the 1966 only used the large center and properly tuned gave about 900 cfm.

 

Now I know the C&D comparison test showed the QJ outperforming the tripower but it was partly 400 vs 389 and partly Milt being under strict instructions for the QJ to be faster. Believe it or Don't.

 

ps the tails were available in different lengths. Mine is the long one. Have several complete A & B body tripowers (might need linkage)…. somewhere.

Edited by padgett (see edit history)

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Back to the original question.

Does a Chevrolet manual tranny work on a Pontiac like this? It would seem to me that they would but what do I know.

If so, look into a five speed from an S-10, They may not be real stout but you did say on the cheap.

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My apologies, I reread and discovered that I misread the "not the cheapest" part.

I still suspect some GM guys here would like to comment.

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14 hours ago, padgett said:

Well sorta. Rochester was pushing the QuadraJet as the answer to everything. Originally 750cfm later there was an 800cfm variant with larger primaries.. And the tiny primarys and metering rods gave a lot better mpg than the 2GC (center carb) of the tripower. Besides the "small center" (pre-1966) was only about 170 cfm while the 1966 only used the large center and properly tuned gave about 900 cfm.

 

Now I know the C&D comparison test showed the QJ outperforming the tripower but it was partly 400 vs 389 and partly Milt being under strict instructions for the QJ to be faster. Believe it or Don't.

 

ps the tails were available in different lengths. Mine is the long one. Have several complete A & B body tripowers (might need linkage)…. somewhere.

People with Tri-power really didn't care about mileage especially since gas was so cheap and if they were concerned they could have bought a Tempest with a 1bbl. OHC SIX.

   The G.M. ( Ed Coles ) ban on multi carburetion hit Pontiac hard. Oldsmobile had finally got it's 3- 2bbl. setup going for 1966. Olds fans lost the J-2 option after 1958 and now after the real car guys at Olds finally got their way with the stuffy old Olds hierarchy the 14th floor ( Ed Cole and his peers ) took it away from them. Buick lost it's 2X4 system as well. Everyone knows Ed Cole has a couple of his baby's over at Chevrolet and guess what? Chevrolet was allowed to keep multi carburetors on the 427 Corvette and also his beloved Corvair. What a corporate political move. Bunkie Knudsen, Pete Estes and John DeLorean ALL had problems with Cole.

 

I have also seen the Pontiac Tri-Power test. But if you perform a apples to apples test ( not a 389 tri-Power against a 400 QJet ) the Tri-power comes out ahead with a 400 against a 400.And I have seen that test.

Pontiac enlarged the 389 to 400 and the 421 to 428, change the valve angle and went to open combustion chambers, straighten the intake runners and install larger valves to get the same HP. THAT's HOW THEY MADE THE SAME HP as the 389 Tri-Power with a 400.

Edited by Pfeil (see edit history)

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GM always played games with HP ratings. In your example the tripower Corvette with solids was rated at 435 hp. But the "for racers only" single quad  L88 was rated at 430 (5 hp less just like the Z28 and the SS-350). In reality the L88 was more like 550 hp. And then in 1967 Pontiac had three different ratings for the same 400 depending on whether in a Firebird, a GTO, or a 2+2.

 

For GM the magic words were "not available with AC" for a really interesting engine.

 

ps in 1985 I was getting 22 highway mpg from a highly tuned SBC with dual quads, at least that is what my Prince On-Board Computer said.

 

MBATR the four speed Muncie bolted the same way (4 bolts) for all GM lines. What was different was the number of splines on the input shaft where it engaged the clutch disk and the bell housings depended on the engine. And yes the S-10 had a five speed but AFAIR the max torque was much less than even the 305 V8, is another item I have somewhere (think I know which pile though).

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14 minutes ago, padgett said:

ps in 1985 I was getting 22 highway mpg from a highly tuned SBC with dual quads, at least that is what my Prince On-Board Computer said.  

 

The computers in our 2000 7.3 Diesel Excursion, and the 2006 Avalanche 8.1L always lie.

WE have the correct size tires,

and the speedometers and odometers on both are dead-accurate with our Garmin GPS,

yet both claim 14 - 18% better mileage than my carefully calculated numbers show.

This has been verified, not over a sigle tank, but over many tens of thousands of miles.

Numbers of actual miles driven, divided by actual gallons used =  true MPG

Edited by Marty Roth (see edit history)
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On 9/12/2019 at 4:32 PM, Robert G. Smits said:

66 GTO 389, 4 speed with 4.11 rear end ratio.  Would like to turn this into a better touring car.  Considering changing the rear end verses going to a Gear Vendor.  Thoughts and recommendations appreciated.  Looking for the best solution, not necessarily the cheapest.  Thanks

 

 Robert, I don't have as much power as you. Having said that, here is my experience.   My 1950 Buick came with 4.10.   I changed to a 3.36.  It could still use a higher ratio for hwy.  In town driving sucks!  If I had it to do over,  and as you have said, cost matters not, an overdrive of some sort would have been used.  There should be several options for the Pontiac.

 

  Good luck.

 

  Ben

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12 hours ago, padgett said:

MBATR the four speed Muncie bolted the same way (4 bolts) for all GM lines. What was different was the number of splines on the input shaft where it engaged the clutch disk and the bell housings depended on the engine. And yes the S-10 had a five speed but AFAIR the max torque was much less than even the 305 V8, is another item I have somewhere (think I know which pile though).

 

Then I suggest a Tremec, Pretty sure they can supply bolt on and up to six speeds.

I have their suggested T-5 behind a 472 cid 525 hp crate Hemi and have had zero problems.

I say suggested because I make tons of torque and they advised that this one will handle it.

Sounds like you may have to swap out a clutch disc.

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17 hours ago, Pfeil said:

P

 

I have also seen the Pontiac Tri-Power test. But if you perform a apples to apples test ( not a 389 tri-Power against a 400 QJet ) the Tri-power comes out ahead with a 400 against a 400.And I have seen that test.

Pontiac enlarged the 389 to 400 and the 421 to 428, change the valve angle and went to open combustion chambers, straighten the intake runners and install larger valves to get the same HP. THAT's HOW THEY MADE THE SAME HP as the 389 Tri-Power with a 400.

 

Tests often show what the tester wishes to show; and that is certainly true with the tripower.

 

Pontiac paid Carter to sabotage the AFB on the mid-60's Pontiacs in order that the standard 4-barrel engine would not out run the more expensive tripower!

 

Of course, the tripower wins the "open hood racing" contests until such time as one looks at a dual quad ;) 

 

As far as the original gear question; not my ballpark, no comment.

 

Jon.

Edited by carbking (see edit history)

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Our 1930 Packard 7-Passenger Touring has a 5.08:1 differential since it was intended to be used between Paris and Monaco, crossing the Alps.

That is fine for city driving, but the 0.70 Overdrive gives the equivalent of a 3.556:1 for country roads. We don't need higher speeds - just fewer engine revs, and it is a pleasure to have both ratios.

 

The intermediate-sized Pontiacwith the "honkin' V-8 has more than enough torque to get moving without slipping the clutch.

 

Enjoy it every day that you can, and smile all the way to the ice cream stand with your bride and grandsons.

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My notes from a while ago for the T-5 was "both world class and non-world class, were rated at 265-lbs.ft. of torque. 1990-’93s were rated at 300-lbs.ft., and the ’93-’96 Cobra “Z-Spec” T-5 was rated at 330-lbs.ft." and why I decided not to bolt my T5 to the GTO RA 400. It may have held it or may need a performance rebuild but been sitting there for about a decade now. Guess I should dig out and see which one it is.

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2 hours ago, carbking said:

 

Tests often show what the tester wishes to show; and that is certainly true with the tripower.

 

Pontiac paid Carter to sabotage the AFB on the mid-60's Pontiacs in order that the standard 4-barrel engine would not out run the more expensive tripower!

 

Of course, the tripower wins the "open hood racing" contests until such time as one looks at a dual quad ;) 

 

As far as the original gear question; not my ballpark, no comment.

 

Jon.

 

 

   The second test I saw was a 400 with a 041 cam Rhoads lifters with a Q-jet on a RA4 intake vs the same car with a 1966 Tri-Power- large center 2GC on the floor dyno-real RW hp. The Tri-Power got it in HP and Torque. That test must have been all of ten years ago. Maybe 15.  

Edited by Pfeil (see edit history)

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Wasn't questioning your mention of the test; I knew of its existence. Questioning the test itself.

 

Pontiac Super Duty Division also tested the tripower, and didn't care for the results. For racing, Pontiac opted for single quad (AFB) and dual quads (AFB).

 

Pontiac sales continued to advertise and sell the tripower, after the street AFB was modified to allow the tripower to outrun the AFB.

 

Pretty conclusive results.

 

Jon.

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Man, you just don't know who to trust anymore !       -    CC 

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Ask Jon about the Carter-Pontiac three barrel carbs. AFAIR the rules of the race organizations restricted the number/size of the carbs and the dual quad NHRA manifold flowed A Lot More than the tripower. Also those A93C triple pots limited the tripower CFM, the single ginormous Air Cleaner for B-body tripowers flowed  much better than the little ones.

 

Which has nothing to do with a good tranny for a GTO. Did find the specs on my T-5 and is a 1352-210 with 3.75 2.19 1.41 1.00 0.72 ratios and a 305 lb-ft torque rating that I was always told was too weak for a RA 400.

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Again thanks for all the replies.  I continue to be amazed at the knowledge on this forum.  I already have 15 inch Rally II's.  Never  heard of the Hone O Drive.  Anyone have any experience?  I think the viable options will begin with a rear end change.  I have found a couple of LeMans rear ends here in Texas but haven't determined the ratio yet.  I can do this in my own shop for not much money.  If unsatisfactory I may add the Tremec or Richmond 4+1 route although the Tremec required major tunnel work.  There are always  trade offs.  May be simpler to just drive my 64 Bonnie with the 421HO and automatic but it is not a convert.  BTW where I grew up in Iowa these were always "GOATS" and proud of it.  A classmate and I drove his new 64 from Iowa City to Houston for interviews and I have been in love with them ever since.

Padgett, didn't they use the later T-5's in Mustangs and Camero"s and isn't there a NWC and  WC class?

Edited by Robert G. Smits
Addition (see edit history)
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Robert - since you mentioned "Bonnie" in your last post, see if you can find a video of the "Bonnie & Clyde" GTO commercial. You will be glad you did.

 

Other monikers other than GOAT for the GTO were "gas, tires, oil; give ticket officer; and girls take over (that was the name of another interesting Pontiac commercial).

 

My solution to the gear issue was to use a lower numeric rear gear with an ultra wide ratio 4-speed. The problem with this is trying to use first gear for WOT. The rear tires object. ;)

 

Padgett - the Carter AFB 3-barrel flowed 939 CFM when flowed on the 4-barrel scale; and 1128 CFM when flowed on the 2-barrel scale.

 

Jon.

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a) more than you ever wanted to know about B-W T5s (now Tremec)

http://www.britishv8.org/Articles/Borg-Warner-T5-ID-Tags.htm

Who said you could use a T5 with a 455 ?

 

b) What Jon is referring to is that 2bbls are measured differently than 4bbls. On the flow bench a 2 bbl is measured at 3" of Hg back pressure. However when 4bbls came along most benches could not manage 3" so they are measured at half that or 1.5" Hg. However a three barrel is neither but flowed 1128 cfb at 3" of Hg and  939 at 1.5".  Isn't linear but not going to get into compressible gas flow theory. Holly also had a 3 bbl but was later. I understand that some thermoquads exceeded 1,000 cfm.

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2 hours ago, padgett said:

Ask Jon about the Carter-Pontiac three barrel carbs. AFAIR the rules of the race organizations restricted the number/size of the carbs and the dual quad NHRA manifold flowed A Lot More than the tripower. Also those A93C triple pots limited the tripower CFM, the single ginormous Air Cleaner for B-body tripowers flowed  much better than the little ones.

 

Which has nothing to do with a good tranny for a GTO. Did find the specs on my T-5 and is a 1352-210 with 3.75 2.19 1.41 1.00 0.72 ratios and a 305 lb-ft torque rating that I was always told was too weak for a RA 400.

 

You mentioned the 421 "B" body cars with Tri-Power. I think starting with the 64 ( maybe 63) cars the 350HP Tri Power used the large air cleaner while the 370 H-O engine used the three pot air cleaners, same true for the 65-66 cars of 356hp using the large single and the 376HP H-O engines using the three pot air cleaners. 

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