What was the reason ?

 

My guess would be it simply made more economic sense to use corporate (chevy engines) in the F-body platform.

Rather than develop two forms of driveline components for each type of motor (Pontiac and Chevy) (Two types of ECM's, two types of motor mounts, passing emmisons, etc...

GM probably saved more money by using corporate power.

 

TAdan hit the nail on the head.It was a corporate decision to use the 305 in both F-bodies.Cadillac I can understand being exempt but I don't understand is how Oldsmobile got away with using thier own V8 after '82 when Pontiac couldn't.Pontiac was planning to use thier 301 and it's turbo version.That's why the T/A-powerbulge hood is offset like the 2nd gen '80-'81 T/A's.It was meant for clearance for the turbo's related plumbing.

 

You mean with the aircleaner sticking out a bit because i always thought the bulge was offset for the plumbling...but the turbo is at the left on the engine
and the bulge is to the right ..strange isn't it ?
I had a 81 TTA and the Turbo was at the left but the bulge is to the right
but the aircleaner was the problem,with a normal hood,won't fit so..it needed the extra space,but maybe...the bulge was functional for air intake purposes....im not sure !
can someone explain me this ?

 

This started several years earlier on the BIRDS anyway. My 79 TA had a OLDS 403 in it from the factory. I am pretty sure that was the first year for that. The 78's had a 400 Pontiac which is the correct way IMO and a stronger more powerful powerplant.

 

Jetmeck you're right about it starting in earlier years.You can find Chevrolet V8's and Buick V6's in many vehicles throughtout the GM line going back to the early '70s.The main reason for the use of the OLDS 403 in the 2nd gen T/A was the phasing down/out of the Poncho 400.You could still get a 400 in '79 but only with a 4 speed and most of them went in 10th Anniversary T/A's.From '82 on it was a management/cost decision to cut down on the number of different engines produced.

On the bulge it was meant for the air cleaner and there was some plan for fresh air intake.At least the 3rd Gen T/A's got the fresh air hood.Another odd fact is when you bought a T/A the aircleaner/shaker was different for the Chevrolet-Pontiac-Oldsmobile engines.

 

I always thought 77 was the last year to have the 400, but I could be wrong

 

Nope 400 /4 speed or 403 OLDS/auto were the options in 79.

 

1976 - Last year for 455
1977 - Olds 703 introduced on Fireird
1978 - unchanged
1979 - First year for 301 Turbo,
1980 - 400 & 403 GONE, only had LG4, 4.9 Turbo, 4.9 & 3.8 V6 options
1981 - Essentially unchanged
1982 - Pontiac motor droped with introduction of the 3rd gen.

The reasons I have heard are\
1) Chevrolet did not want the Firebird to potentially outperform the Corvette, If development continued like it did on the 3.8L Buick Turbo then it would have put the Vette in second place for performance "Sports" Car.
2) The 301 Turbo had lack luster performance gains for the extra investment. Pontiac basically gave up on the development. Interestinly some owners have reported significant gains by some minor changes.
3) GM wanted to go more Universal with its engines, although it started out as a "Small Block Chevy" GM wanted to mainstrem its engine developments. IN the early 80's Pontiac retained the 2.8 Engine, Olds had the 307, Buick had the 3.8L later called the 3800. Cadillac was off in its own world and until more recently had its own power plants. THe other engine in 1982 was the Iron DUke, Although I know very little about the I4 engine apparently its a SB Chevy engine cut in half, The 4.3 V6 was a SBC less 2 cylenders in the front.

Hope that helps.

John

 

The 1982 T/A was planned to be introduced with a turbo 301 but due to packaging issues and the inability to meet the stricter emissions requirements at the time and still have some level of performance the decision was made to use the Chevrolet 305 in both cars.
----------
Also, the 2.8 V6 was a Chevy engine and the Iron Duke 2.5 liter 4 cyl was a Pontiac.

 

Just a note, from 77-78 there was a little power increase.

 

yea, 20hp difference. Also, only W72 packages had the 400 in 79 and were only available with 4 speed as stated above. There weren't but a couple of hundred of these made. 77 was the first year for the 403, mostly available only in CA at first and had only 180 hp.

 

Technically there was no power increases from 1970 until 1983, it was a steady decline. Then in 1984 & 1985 thru today there has been a steady increase.



JOhn

 

70-71, intro of the 455:less hp, more torque.
78-79 more horsepower
79-80, more torque with the 4.9 turbo, but less horsepower.

 

The 403 was used from 77-79, and always came with 185 HP, regardless if it was Cali, high altitude, or federal.
The 301 also came out in 1977, but was not offered in the T/A until 1979, and then only as a credit delete option, and also could be had with a 4 spd,as the 403 was standard.
The 301 Turbo didn't come out until 1980.
The power increase I saw happening in the late 70's were with the 77 Pontiac 400, while the base 400 was rates at 180 HP, the w72 400s were rates at 220 HP.This stayed the same until 1979.
The 301 Turbo, in 1980, then went down to 210 HP, and would remain the highest HP engine used in a T/A, until 1985, when the 215 HP 305 TPI came out as the top engine option in the T/A.

Leon

 

75-76 TA 455, ONLY 4speeds

 

Technically, that's not right.
The 1976 455 was only rated at 200 HP, and was the highest HP engine in the lineup. Then the w72 400, from 77-79, had 220 HP and the 301T had more HP than the old 455, but nowhere near the torque.

Leon

 

Actually, the 2.8 was a Chevy engine, not Pontiac.
Cadillac actually used alot of 307 olds engines in their cars, in the 80s.
And the Iron Duke used the same pistons as the 301 Pontiac, as it was made by Pontiac, and had nothing to do with the Chevy small block.

Leon

 

for the most part now adays everything that GM makes has a GM (or chevy motor) in it

 

It was a corporate decision.
Chevy got to build 4, 6, 8 cyl
Olds got to build 4 and 8 cyl
Pontiac got to build 4 cyl
Buick got to build 6 cyl
Cadillac got to build 8 cyl

That was pretty much about it from what I remember. The Olds probably was in favor of the Pontiac 301 because it outperformed it and got better ecomony. Have to remember CAFE was pretty big back then. The 301 was a dog on all fronts. No power and drank fuel almost as bad as the 400.