Hot Rods Pontiac Superduty 421 experts

I would like to start a thread about those awesome engines from the 60's. If you have experience in this subject then let's talk. Clear up some misconceptions and share information on where they are and what's for sale.


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I don't have have any first hand knowledge of these engines, but have always been impressed by what they were capable of.

Looking forward to hearing what other members have to say

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Somewhere in the files I have a '62 "Special Equipment" specs & order form brochure. If lucky enough to find it, we'll get some factory info for you.
One tidbit always comes to mind - the 405 horse Super Duty option was $1200 plus, & you (the guy taking the order) made the customer state the car would not be operated as a "normal passenger car".
And don't ever turn down a ride in a '66 2+2 4 gear car ....

 

Watching this thread too. I knew a guy way too many years ago that put a 421 in a 65 Goat. Jeeezus that thing would go.

 

Be a good time to recall that SuperDuty Tempest that was abandoned to settle the estate, the junkman didn't have room to haul it away and the deceased's nephew put it up on ebay to get rid it. That was quite a story, every now and then there'd be updates on its restoration. It was one of six I believe, just an abandoned delerect outside a guys garage.

 

Sitting here savoring the memory of my friend Tony's C's maroon 66 GTO with a tri carb 421 with 4.33 rear gears. The words "scary fast" are the most suitable two words I can use to describe this car. 51 years later I still smile thinking about how fast that car was.

 

I opened this thread just to see how long it would take for someone to call the 421 a big block Pontiac....

Beyond the smart ass-ness that I am sometimes afflicted with, here is some more good information.

http://www.oldride.com/library/1962_pontiac_super_duty.html

 

Thanks. I have this in my history file. Anybody have any parts for sale?


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One story I always heard was that you couldn't run the engine longer than (insert ridiculously short amount of time) if it had the aluminum exhaust manifolds, because they would melt. Seems unlikely. Cast aluminum melts at 1200 degrees. Is it possible?

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I researched the SD carburetors many years ago (before Carter was bought by F/M). One piece of trivia for the SD engines, is the first to use a "3-barrel" that was converted from a 4-barrel.



Jon

 

One other fact about the SD's that probably will not play well on this forum. Pontiac engineers tested the legendary tripower, even casting an aluminum manifold for the SD, and found it was not competitive; and immediately discontinued the tripower. So the SD's used, depending on the venue; (1) a single four-barrel, (2) dual four-barrels, or (3) a single three-barrel. Tripowers were relegated to the non-racing engines to customers that believed the hype.

Jon.

 

I had a modified 421 tri power in a 65 goat for several years. I understand that the super duty was more powerful but WOW is the best description as to what that tri power would do. Still have the engine, the car is long gone.

 

Ironic. T've got a '64 GTO with a factory '66 Catalina 421 Tri-power engine in it. When I put a new frame under it, I replaced the SP-200 automatic with a rebuilt M21. The car is a beast.





Allan

 

My brother in law and me restored an original 62 Aluminum SD back in the eighties. I worked at the Pontiac dealership where it was purchased in 1962. It now sits in a museum in Tennessee. He still owns the car and I have many memories when we raced it in New England.

 

I don't recall an aluminum tri-power manifold for the SD but for sure it was catalogued in the early sixties. I think it was done for the 389 HD. The Heavy Duty (HD) program was the forerunner to the SD. Pontiac was heavily into NASCAR with Smokey Yunick, Ray Nichels and others and they developed suspension and engine parts for oval racing in addition to the drags. HD parts were strictly over the counter and as a result not legal for S/S, but there was also O/SS then, maybe that stuff was legal for the Optional/SS cars.
HD stuff included solid lifter cams, aluminum 4 bbl. and 3-2 manifolds, dual point distributors, heads with bigger ports, valves and screw in studs with guide plates. Then there were special spindles and metallic brake packages, clutches and flywheels, and I'm sure a lot more.
Back in the early '80's I saw and passed on an aluminum HD tri-power manifold at the Jefferson, WI swap. Being a hard core Chevy guy I didn't buy it, and it was cheap too! Stupid.

 

I'm calling "face" on this picture. And not surprisingly, it appears to be smiling!

 

Just copied that link, lots of information.

The mighty 421 Super Duty Engine. Differences on this engine are the Alternator and brackets. 1962 421 SD engines were equipped with a generator. This engine is also equipped with Aluminum Exhaust Manifolds which would simply melt if subjected to ordinary street use due to the excessive heat. The engine was rated at 405HP, but its true output was much higher.

1962 Pontiac Super Duty - 421
It stands without question that the 1962 Pontiac Super Duty was Pontiac's pinnacle year in drag racing, NASCAR and other racing events. Pontiac was on top of its game in 1962, following a mandate handed down by the officials of the NHRA, vehicles wanting to race in the Super Stock class must be Factory released. In previous years Pontiac got away with shipping factory low-compression equipped vehicles to racing super stars like Mickey Thompson and Arnie "The Farmer" Beswick. Hidden in the trunks however were the racing goodies, Forged Steel 421 Blocks, Forged Pistons, Forged Crankshafts, assembled high compression heads (#127) and many other racing goodies.

All late 421 engine blocks were produced with a .030-inch overbore, technically giving the engine 428 cubic inches. Cylinder heads are the 1960-1961 high-performance type with 1.92-inch valves and 1.66 exhausts, undercut valve heads and 1.65-to-1 rocker arm ratio to give it high valve lift without excessive acceleration of the lifter-pushrod mass. The cam was a No. 10 McKeller solid lifter giving it 308 degrees intake duration and 320 degrees of exhaust. Factory recommendations state a maximum of 5500 rpm with the standard dual valve springs.

Lower engine components include special heavy duty connecting rods, Moraine aluminum bearings, Mickey Thompson forged pistons giving it 11.0-to-1 compression, four bolt main bearing caps, heavy duty oil pump and special six-quart oil pan, light weight flywheel with heavy duty clutch and clutch counter-shaft.

Typically the engines were setup loose from the factory for minimum friction. Pistons were .009-.013 inch skirt clearance, .002-.003 bearing clearance, with .030-.035 side clearance on the rods. Piston Slap sounded like a boiler factory when started cold and improved only slightly when warm!

Carbs included two big Carter AFB four-barrel carbs mounted on an aluminum manifold, which did not include a provision for exhaust heat in cold weather. Carter AFB carb numbers were 3433S FRONT and 3435S REAR, manual choke style system was provided, throttle linkage was straight mechanical style.

Special dual-point distributor had no vacuum advance and uses allot of spark advance. Factory recommendations include an initial setting of 10 crank degrees with another 27 degrees in the distributor achieving a healthy 37 crank degrees advance on the top end.

Exhaust system used the unique "Pulse-Flow" dual-outlet cast-iron exhaust headers with huge 3-inch outlets, two on each side. Special casting which bolts to the header outlet flange with a 3 inch opening on the side and an adapter for a 2.25 inch exhaust pipe on the back. Side openings can be uncapped to free the exhaust during a drag race. When capped exhaust flows through dual low-restriction mufflers that give a maximum of quieting with minimum backpressure.

1962 Pontiac Super Duty Engine Codes


Mid-1962 Pontiac released a second version of their outstanding head design, this time released under the part number #541127. These heads increased the valve size to 1.96 intake and 2.02 exhaust. It also increased the compression ratio to 12.5:1, later version of the Super Duty 421 would increase to 14.5:1.

Engine Specifications

• All late 421 engine blocks were produced with a .030-inch overbore, technically giving the engine 428 cubic inches.
• Cylinder heads - high-performance type with 1.92-inch valves and 1.66 exhausts, undercut valve heads and 1.65-to-1 rocker arm ratio to give it high valve lift without excessive acceleration of the lifter-pushrod mass.
• Camshaft - No. 10 McKeller solid lifter giving it 308 degrees intake duration and 320 degrees of exhaust. Factory recommendations state a maximum of 5500 rpm with the standard dual valve springs.
• Heavy Duty connecting rods
• Moraine aluminum bearings
• Mickey Thompson forged pistons giving it 11.0-to-1 compression (Typically the engines were setup loose from the factory for minimum friction. Pistons were .009-.013 inch skirt clearance, .002-.003 bearing clearance, with .030-.035 side clearance on the rods. Piston Slap sounded like a boiler factory when started cold and improved only slightly when warm!)
• Four bolt main bearing caps
• Heavy Duty oil pump and special six-quart oil pan
• Light weight flywheel with heavy duty clutch and clutch counter-shaft.
• Carter AFB four-barrel carbs mounted on an aluminum manifold, which did not include a provision for exhaust heat in cold weather. Carter AFB carb numbers were 3433S FRONT and 3435S REAR, manual choke style system was provided, throttle linkage was straight mechanical style
• Dual-point distributor, no vacuum advance and uses allot of spark advance. Factory recommendations include an initial setting of 10 crank degrees with another 27 degrees in the distributor achieving a healthy 37 crank degrees advance on the top end.
• Unique "Pulse-Flow" dual-outlet cast-iron exhaust headers with huge 3-inch outlets, two on each side. Special casting which bolts to the header outlet flange with a 3 inch opening on the side and an adapter for a 2.25 inch exhaust pipe on the back. Side openings can be uncapped to free the exhaust during a drag race. When capped, exhaust flows through dual low-restriction mufflers that give a maximum of quieting with minimum back pressure.

 

Barry Moore, a friend who was also 19 in 1963, talked his wealthy father into buying a new '63 Super Duty Catalina lightweight (not a Swisscheese) for him. It was one of the fastest cars on the streets of Charlotte N.C. that year. He often talked to Arnie Beswick and bought some parts from him to make it faster. All the guys wanted to ride around with him knowing he would find a race before he decided to go home......I was one of them. He would only let us ride with him one at a time to save weight. He never got beat when I was the lucky one riding with him. He blew the engine in it about a year after getting it and it never saw the street again while he owned it. He died very young and the car sat at his parents house until his father sold it with the engine out of the car. By then it didn't have much value.
I can't get that car out my mind and wonder where it is today.

 

This guy seems to be our resident Pontiac expert has some build threads and this one on building a 421

http://www.jalopyjournal.com/forum/threads/1964-pontiac-421-ho-engine-build.969317/

I sent him a pm maybe he will jump in.

 

NASCAR


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NASCAR used them. I have one with the dual accelerator pump jets.




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Not a Super Duty but a pretty rare bird: A good friend of mine has a 1963 Grand Prix that has a factory 421 with 4 speed. I looked it up once and I think it was one of 223 built. I thought I had a pic of it around somewhere but can't find it at the moment. It was originally Daytona Blue(that is what Chevy called it)with a black vinyl roof and blue leather interior. It has since had some custom work done to it so it is far from original now but is still a looker...........and it does git and s**t!

 

Seems there is something different with the distributor gears on a super duty 421. I believe the gear was a larger diameter or something..can't remember now.
I got a buddy here in town with a maroon 57 Pontiac two door sedan, axle under the front and a 421/4 speed in it. Dont' know if it's a super duty or even what year the motor is. Said to be quick but he hasn't had it out in several years and I've never gotten a a ride in it....yet.

 

Around 1991 I sold some Rallye I's to Phil Heck. In his garage was the rarest Pontiac piece I have ever seen, an aluminum frame for a '62 or '63. Built by A O Smith, he had aquired it from Selden Ruwwe. I had no clue what it was when he insisted I grab ahold of it and move it from where he had it leaning against a wall. I heard he had it for sale a few years later. I wonder if he still has it.

 

One of my street racing rivals back in the 60's ran an 421 Catalina 4 speed. I had a 406 tri-power Galaxie 4 speed.
We had some great races. If I did not hole shot him, it was over in second gear that Pontiac pulled so hard on the big end.
The closest drag strip was 3 hours so the back roads were our only choice.

 

Great input and stories of the glory days of the Super Duty era. Keep them coming.
If there are a pair of SD VALVE COVERS with the long oil filler tubes out there, I would love to have them. Contact me me at domdankins@ gmail.com. Last piece to the puzzle for my MT SD.


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I'm not a metallurgist nor have I seen a photo of a header(s) melted down from use in drag racing the SD Pontiacs.
I think this is possibly an urban myth.
Can anyone weigh in on this that has definitive proof of this phenomena?
Personally, I have mine jet coated inside just in case the heat monster comes after me!


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Do you mean with a pump circuit on the secondary side, or with dual accelerator pump wells? Never seen or heard about either on a Carter. But then I'd never seen the 3 barrel version either until Carbking posted this picture.

 

I used to have the super duty dealer supplement manual and as I recall, it had a specific warning about operating an aluminum header car at sustained speeds or they would be damaged. this was printed in big bold letters.

 

Found my research on the carbs from so long ago. All of the SD carbs (except the discontined tripower which were Rochesters) were Carter AFB's with the single exception of the "idling" carb which was also Carter.

Just for the record, the standard tripower manifold in 1960 was 532422, the Super Duty (cast iron) manifold in 1960 was 535552, and the aluminum Super Duty tripower manifold for 1961 was 540510. I have been unable to detect any differences from the standard 532422 and SD 535552 manifolds other than the number; but I have NOT cut one of each apart to measure runner volume.

1960 - Difficult to tell EXACTLY when Pontiac changed designations from "heavy duty" to "super duty". Since both Carter and Pontiac refer to this carb as Super Duty, I am listing it as such:

Carter AFB 3010s Pontiac 434628 625 CFM auto choke.

Two of these carbs were used the first time the dual quads appeared in 1961, with the auto choke springs turned backwards to keep the chokes always open. There is a picture of this set-up in Pete McCarthy's book.

1961 - Tempest only - Carter 3266s Pontiac 540873 625 CFM auto choke
1961 - Carter 3298s Pontiac 535499 625 CFM manual choke
1962 - Dual quads Carter 3433s Pontiac 543780 625 CFM front
Carter 3435s Pontiac 543817 625 CFM rear
1962 - 3443s Pontiac 543889 750 CFM
1962 - 3444s Pontiac 544121 675 CFM
1962 - 3596s Pontiac 9772048 750 CFM (late, for 1963)
1963 - 3636s Pontiac 9772389 939 CFM

The 3443s, 3444s, and 3596s were sold to be used either as a single four, or on the dual four intake(s)

SPECULATION!!! It is well known in Pontiac circles about the bathtub carb with its "idling" carburetor (a single-barrel set between the dual four-barrels). I could find NO ABSOLUTE documentation on this, but apparently Carter did supply Pontiac with (6) six experimental YH carbs number 3391s. The carburetor never went into production, and I can find no record that a Pontiac part number was issued. So speculating that this was the idling carburetor.

Jon.