Topic: Olds 403 or Pontiac 400

[jonathonar89]

I've heard time and time again from so many Trans Am owners about how much the Oldsmobile 403 sucks.  Why do people say this?  Is there any reason why people stay away from them like it's the plague?

[RainMan]

The design does have some limitations due to the siamesed cylinders and windowed webs.The main bearing webs are the weak link and the engines can usually accept only a .040 overbore. They are thin

[hada76]

i think its more of a pontiac purist thing.  (PONTIAC CAR=PONTIAC MOTOR)  same with the SBCs

[RENOVATIONS]

True...a lot of people look at cars with "corporate engines" as less than genuine and are prejudiced towards them regardless.

[transam dave]

THE way i feel is the 403 olds motor is a transam motor.I really love the power it sends to the driver as it roars down the highways. just my opinion as i have had alot of 403 transams love em all.

[Joker (§ir£Ğragon)]

People fear what they don't understand.

[Helter80]

my TA has a 403. i do not mind it. being is that is what my car came with from the factory, i would prefer it to have that other than any engine. its just because i like my car being stock, and originality. i do not mind it being an Olds motor also because a Trans Am came with them in 79.

[Maryland Bandit]

EXACTLY!! I've worked on both. The 403 in my opinion, is easier to work on then the 400.

[brian c]

If both engines are built to the same specs, they will last equally long under the same driving conditions.

That's true of any engine - Chevy, Olds, Pontiac, Caddy, Buick, etc.

[jphillips3333]

All the 403 guys want Pontiac motors ... it's just a fact of life. 


                              Ooof ... did I say that out loud.

[Joker (§ir£Ğragon)]

All the 403 guys want Pontiac motors ... it's just a fact of life. 

Pontiac guys want that to be true so the value of their engines would go up.

[jphillips3333]

I typically read about the 403 to 400 swap vs. the other way around.  It's good to be right 

[hada76]

why did GM pick that motor?  just had a pile of em layin around?

[72blackbird]

Pontiac probably was running short on the 400's and Olds had a warehouse full of 403's- I guess they had to go somewhere.  

The only thing I don't like about the 403 is the windowed main design of the block- when I saw that I knew that wasn't the greatest day for GM engineering (probably the same guys who designed the 500557 block).

Geno

[Rick]

why did GM pick that motor?  just had a pile of em layin around?

Prime considerations for engine selection at that time were manufacturing cost and ease of emissions control certifications.  Performance was a non-starter to the bean counters by that point.  Couple it with the CAFE requirements and the fact that most Firebirds with large displacement engines were built with automatic transmissions and the Olds 403 floats to the top of the pile.  You'll note that shortly after Pontiac ran out of 400s for the 4 speed cars, engines that were 400+ CID the TA was suddenly not available with a large displacement.