Looking at the recent ebay offering of that '63 Tempest, I was wondering about the transaxle. Was that a "purpose built" SD unit made just for the 421?? Or was that a off-the-shelf 326 unit?? If it is indeed a SD unit, then does it means there are only 12 of those built too?? :eek2: :eek2: Talk about unobtanium parts!:dollar: :dollar: :dollar: :dollar:
According to the Yenko site, a deal has been struck for the original Aluminium front end to be reunited with the car and a transaxle has been located. I guess it helps when you have money!!ou: I also saw that someone was gritching that the car would not be worth as much since it did not have the original block!!!:error: For goodness sakes, it was a race car!! Someone hit the nail on the head when they said, "if it was a race car and still had the original block, it might not have been much of a racecar!!!" :TU:
Yes - it was a purpose built transaxle. Brian Stefina can probably comment better, but essentially it was two powerglide tranmissions bolted together to make an automatic four speed. The car was launched with the clutch pedal and then the shifts were made automatically after that. The base 63 Tempest was a crazy vehicle, with the rope driveshaft and rear swing arm suspension; these Super Duty cars were crazier yet! K
The base 63 Tempest was a crazy vehicle, with the rope driveshaft and rear swing arm suspension; these Super Duty cars were crazier yet! K[/QUOTE] Note the swing axle part. Most of these cars were converted to a live axle and front mounted T-10 because they had trouble making them hook. When they squatted off the line, the wheels went into insant negative camber, and you lost half the grip. Also tried was stiffening the rear springs until the rear suspension was almost solid, in order to keep the tires perpendicular to the ground.. Brian?
The engines and transmissions (4 speed automatic) were "purpose built" for the LeMans / Tempest cars that they were going in, and had a different crankshaft, intake, heads and headers than the engines slated for the full size cars. There were actually 14 cars built, 2 early Tempest coupes, 6 LeMans coupes and 6 Tempest wagons. The difference between a Tempest and a LeMans was most identifiable by the tail lights. LeMans had a rectangular lights that were arranged sideways, one per side, and the Tempests had two round tail lights, one above the other on each side.The transmission was built by using 2 two speed automatics arranged around a rear center section, with half of the trans ahead of the center section and the other half behind the center section. Brian Stefina could give you more information, since he has had "hands on" experience with them. This is what the flywheel end of the crank looked like, but the flywheel wasn't bolted to the end of the crank, an adapter was bolted on there and attached the "rope driveshaft" to the engine. The flywheel was attached to the back of the transmission, behind the rear axle. Some pictures of interest are at this link. Click the pictures for a better look. http://www.1963pontiac.com/book.htm I've had a copy of this book, Pontiac Musclecar Performance 1955-1978 - By Pete McCarthy, for years, and it's worth having to identify Super Duty Pontiac cars and parts, and to read the history of the Super Duty cars and parts program since 1956. Lots of pictures, vin numbers, casting and part numbers, engine identification, even gives casting number to date timelines on some castings. I understand some of the information may need updating (maybe it is done before each new printing) , especially since this car has been found. Book was first printed in 1987 I believe.
As far as that transaxle is concerned, Brian is hands-down the only one that has laid hands on one that has "EXP" (experimental) stamped on parts. This was for the wagon. Maybe he'll be commissioned to do the trans axe in this one too ????????
Some of the unique stuff: There was an additonal two speed added to the rear behind the diff, the addition had a unique case, small sump linked via a tube to the pan, external line to feed the servo and a modified planetary (no reverse needed in the addition). The diff had an insert in the carrier making it a spool. Not a standard Tempest Torque spline, bearings or seals. I think it was Beswick who said the ring and pinion had to be replaced every 8 to 10 runs. The valve body was unique, being a full manual. As I recall the shift strategy was rear trans to front, 1st = 1st + 1st, 2nd = 1st + 2nd, 3rd = 2nd + 1st, 4th = 2nd + 2nd. The flywheel ran on a bearing support, the pressure plate was modified for the input shaft (from engine) and the disk was splined to the trans input. The pressure plate was operated via a hydraulic throwout bearing.
I guess bolting a 4 speed behind the 421 and mounting a solid axle at the rear was just too much work, eh? :idea2: Did they really think that a "sportscar" rear end was going to work at the dragstrip behind a 421? Just looking at the complexity of the drivetrain automatically spells "disaster".
The diff only had one input. The mainshaft ran from the front to the clutch in the rear, through the hollow front to rear trans shaft which was through the hollow pinion shaft. So input torque went via a 3/4" solid shaft, through the front, diff and rear units to the clutch, from the clutch into the rear unit, the rear unit output went via a hollow shaft, through the diff into the front unit, the front unit output went into the diff. Cool huh.:TU:
Brian, Totally different setup. Corvettes have an independent setup, the SD's had swing axles, Think VW Beetle.
The Stan Antlocer 1963 SD421 Lemans (Stan Long Pontiac) was the one in the E-Bay auction. Stan Antlocer actually fitted his car with a 3-speed auto trans and a conventional rear axle back in 1963, and was billed for a short period of time as "The World's Fastest Tempest". These special 1963 SD421 Lemans Coupes and Tempest Wagons were the pinnacle of GM's involvement in drag racing, until the "no racing" mandate hit in Jan 63. They were way over the top, but along with the SD421 Swiss Cheese Catalinas, these cars put many of the famed Mopar factory teams on the trailer. I actually own one of these rare cars, and I left it the way it was delivered. It's never been raced. http://www.diecastfast.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=DCF&Product_Code=H61-50148 :bla:
I actually own(ed) one as well, but am sad to report it was stolen(!) from my desk over the July shutdown... (Mike - can I have it back?) The Delorean coupe is the car that started a two generation obsession with Pontiacs for me and my Dad. K
LOL! The geometry is terrible! I decided one day I was going to jack my '63 Lemans convertible up under the rear diff in order to scoot it over... ...it ain't gonna' happen... The car kept going up and up and the tires kept going down and down. They never did come off the ground (there's nothing to constrain them). I finally gave up and got the car skates out and did it like you're supposed to... p
