bits of pontiac tech you may not know

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
http://www.pontiacsafari.com/EngineCooling/index.htm

http://community.fortunecity.ws/silverstone/pontiac/101/tech/cams.htm

http://enginefacts.com/pontiac389.php

http://garage.grumpysperformance.com/index.php?threads/some-pontiac-related-links.4125/#post-42587

389 V8 Engine

The Pontiac 389 V8 was first introduced in 1959 and would become one of the most popular engines of the muscle car era. The engine evolved from the Pontiac 370 in which the stroke was increased. There were a lot of changes to the 389 during its eight year production run which gained the engine even more notoriety. Most experts agree that the 389 was one of the key factors in starting the muscle car wars of the 60s.
One of the first major changes for the 389 came in 1960 when Pontiac stopped using its “reverse flow” cooling option for the powerful V8. From 1955 to 1959, Pontiac had used a cooling system (and some GM motors still use it today) where the coolant was sent to the heads first and then down through the block. The idea behind “reverse flow” was to keep the heads cooler because of the large problem with engines in the 50s burning up and warping the valves. By 1960 GM had started using harder and more reliable valves and seats for their engine heads which let them do away with the “reverse flow” cooling method. For more information on “reverse flow” and why Pontiac stopped using it check out this interesting site.
All Pontiac V8s from 1955 to 1959 were reverse cooled, known as the "gusher" cooling system. It was removed from the design for the 1960 model year because designers moved the generator and the power steering pump from atop the front of the engine down to the front of the heads to accommodate a lower hoodline. However, the 1959 389 engines had the generator in front of the heads with reverse flow cooling still in use. This suggests that the cost of the reverse cooling was the reason for the change to "equa-flow" cooling.
The 389 was also the first engine by Pontiac to come with the S.D. (Super Duty) option. If you are lucky enough to find a 389 S.D. engine then you will have quite an impressive setup such as a four bolt main engine block and a forged steel crankshaft and connecting rods. These Super Duty 389 engines were mainly used for NASCAR racing but a small amount of them offered for sale to the public in order to meet NASCAR standards.

Another impressive version of the 389 introduced in 1959 was the Tempest model. The Tempest 389 engines were also known as “420-A” motors and came with higher compression as well as better performance options. These engines were available up through 1962 and produced up to 348 horsepower which was the highest power output a factory 389 engine would ever see with the Tri-Power carb setup.

The 389 Pontiac motor also has the coveted award as being the first engine used in one of the most famous muscle cars of all times, the Pontiac GTO. The GTO is considered by many automotive enthusiasts to be first real muscle car on the block even though it’s a discussion that could be debated. By the end of 1966 the last of 389 engines rolled off the assembly line to be replaced by the Pontiac 400 but it didn’t leave without leaving a lasting legacy on the automotive world that will never be forgotten.

Today, engine parts for the 389 are in abundant supply especially if you are looking to push up the factory horsepower. Most any performance auto part stores will have quite a nice inventory of carburetors, headers, cams and many other engine parts that can really give your 389 quite an increase in power and performance.


Pontiac 400 V8 Engine


The Pontiac 400 6.6 Liter engine was first introduced in 1967. This version of the Pontiac V8 engine was used in the GTO, Firebird, and the Trans-Am Firebird.
The 400 was inspired by the Pontiac 389 V8 and proved to be the last Pontiac engine with closed chambered heads. At the start of the 1970s, the 400 V8 generated more than 300 horsepower, but decreased to 180 horsepower by the time the last 400 engine was produced in 1978. The special edition black and gold Trans Am made famous by Burt Reynolds in the Smokey and the Bandit movie franchise increased Firebird sales in 1977 and 1978 and made the 400 V8 quite popular. Even though production of the 400 had ceased, 1979 Pontiac models still featured the 400 engine due to large stockpiles left over from the previous year.

In 1980, Pontiac decided to use the Pontiac 301, 4.9 V8 engine to replace the 400. Sales and the new engine’s performance failed miserably and the 301 was no longer offered by Pontiac after 1981.

Pontiac 421 V8 Engine
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In 1961 Pontiac continued to push the horsepower upwards with the release of the 421 engine. As with all other Pontiac V8 motors that evolved from the 316 V8, the 421 was simply a bored out and stroked version of the popular Pontiac 389 V8. What was most interesting about the 421 engine in the beginning was that it was a dealer installed option only known as the SD (Super Duty) 421. These motors were built mainly for NASCAR or other racing purposes and were equipped with all the extra racing goodies that people were looking for. A Pontiac SD 421 came with forged steel rods and crankshafts for extra durability. In 1961 and 1962 they were available with either one 4 barrel carburetor or a dual 4 barrel carburetor setup depending on whether the buyer wanted to head to the racetrack or drag strip.
By 1963 Pontiac decided it was time to release the 421 V8 officially to the general public and the motor would continue to be available until the end of the 1966 model year. The 421 SD Tri-Power engine offered during these years produced the highest horsepower of any motor in the Pontiac V8 lineup at 376 bhp. There were a few 1962 Grand Prix models that came with a 421 SD from the factory so if someone is lucky enough to have one today then they have a car that is probably worth some decent money simply because of the rarity of these models.
 
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Pontiac 428 V8 Engine


The Pontiac 428 was introduced at the same time as the Pontiac 400 V8 in 1967 and used primarily in the Grand Prix, but also for the legendary GTO and Firebird models.
Although the 428 was modeled after the Pontiac 421, it had a cast iron crankshaft rather than the steel used in the 421. The 428 was one of the "long journal" V8 engines that Pontiac produced.

Because the 428 was used only in large cars like the GTO and Firebird and featured prominently in NASCAR stock cars, it was quickly replaced by the Pontiac 455 in 1970. The higher output 428 engines featured 1.91 inch valves and a 1.66 inch exhaust.

Pontiac 455 V8 Engine


The 455 Pontiac V8 was introduced in 1970 and provided large-bodied Pontiacs a torque-friendly engine. Prominently featured in the Pontiac Bonneville, the 455 was also used in the GTO, Trans Am, and the Firebird.
The 455 was an improvement on the Pontiac 428 V8. High Output and Super Duty versions of the 455 were added in succeeding years. The Pontiac Grand Ville series also featured the 455 beginning in 1972.

Although the 455 has great torque, the 455’s horsepower was often adjusted due to various emissions changes, advertising gimmicks, or to appease insurance companies. The 455 High Output engine had improved cylinder heads as well as better intake and exhaust ports while the Super Duty, made in 1973, was able to produce 290 horsepower in spite of more strict emissions standards. The 455 was discontinued after 1976.
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http://www.tinindianperformance.com/KRE aluminum Pontiac timing cover.htm


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http://www.classicindustries.com/product/firebird/parts/f140.html

http://www.summitracing.com/parts/bra-1649

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http://www.ebay.com/itm/1964-1968-GTO-LEMANS-TEMPEST-WATER-PUMP-W-CAST-IMPELLER-/231833400442?fits=Model:LeMans|Make:pontiac&vxp=mtr&hash=item
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preferred CAST IMPELLER ABOVE
LESS EFFICIENT STAMPED IMPELLER BELOW
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Something that always puzzled me was Pontiacs use of the name Super Duty and Super Duty hood scoops that were Ford Super Duty truck hood scoops with out the chrome grilles. I can understand Pontiac using the Ford truck scoops as they were a natural fit but the name Super Duty??
The earliest Pontiac reference to the Super Duty name that I ever found was for 1961.
Ford used the Super Duty name and hood scoop in 1959 and maybe earlier.
I'm Canadian so we didn't get many Pontiac engines here until 1970 so Pontiac history isn't ingrained here like the U.S.
Any input is appreciated as to why Pontiac used the Ford Super Duty name on its high performance efforts.

Thanks
Randy

1959 SUPER DUTY.jpg 1960 SUPER DUTY.jpg
 
There is a Typo error Grumpy.
428 Pontiacs had 2.11 inch intake valves.
And 1.77 " exhaust valves.
There may have been a 2bbl 428.
I don't recall tonight. With 1.96" intake valves.
 
The guys are looking for me on DC.
Started a thread to my whereabouts .
Let them know I am here on your sight.
 
ok. I posted a link and the info your here!
 
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I'm waiting on a call back on a 1970 Pontiac 455 for sale. The ad only says it runs good. And the title description says "GTO" price is $1250. Get it? Is there a poor 455 in 1970?

Also, in a publication ad there is an intake for sale. Says its a 72 ram air IV for $750. P/n 488945. Is this a good deal? A real number?
 
Yes check out the 1970 455 Richard.
I like buying from Old Timers when I can.
Sometimes the mind gets Foggy.
Does not mean they are not Honest.

A real GTO Or Grand Prix 455 has 4-bolt main caps.
I have had excellent luck with 2-bolt 1970 Pontiac 455 blocks. The Main Caps are Huge and thick either style. 1/2 inch bolts.
Only the Big Block Chevy has similar design criteria to take Severe abuse.

Right now everything is advertised as Ram Air 4 I have noticed too.

Waking up yet.
I will check the Intake number for You.
Don't forget we have Grumpys site.
He has lots of Pontiac info here also.
Most is accurate.
 
I am going to busy later today.
Tearing down my Olds 425.
Its Virgin 1965 never taken apart.
I only removed the Valvecovers to inspect.
I bought it from an Old Timer like Grumpy.
I know its a Good One.
Made another order to Summit Racing yesterday . The last few items are on thier way.
Just Need Motor oil now.
My Castol 10W30 oil for break in.
2 - 5 Quart containers from Walley World.

2 - 5 Quart Black Jugs of my Castrol Edge 10W30 synthetic oil to run after the Rings are sealed.
Been talking to my Bud Steve with his machine shop.
Get it done.
 
Please let me know if that intake is worth grabbing before someone else gets it, same for the 455. I know after 70 the the 455 have 8.2 to 8.5 compression and hp can be as low as 180. My plan is to get this while it's available and if I never get to do anything with it and want to sell it I'm not going to lose to much.
 
I spoke to the seller, he's an hour away. Says its been sitting in his shed for about 5 years, ran when he bought it from a friend. Came from a bonniville he thinks. It's all stock. My books don't cover info on 1969 and 70 so I'm sort of stuck if I have to move fast. I need to know the numbers to look for or stay away from
 
Part #488945
heat cross overs seperate
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What ever you want to pay Richard.
1970 Bonneville 455 is a good engine.
Borderline running on 93 octane pump gas today as is.
 
Besides whether this intake is rare or not, is there a justifiable increase in hp or torque over any other intake?
Why the separation of the heat cross over? Is it just a complex casting issue or a performance benefit?
 
It may be Folklore but the 1969-70 Ram Air 4 Intakes flow superior to the 1971-72 HO 455 Aluminum intakes.
Main advantage is its lighter than iron.
1972 455 HO intake is rare.
 
750 Is average sale value of 1969-72 455 HO Intakes with crossover.
 
Its a real precision cast intake.
Made by Winters Foundry for GM.
 
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