Family member is asking me to look for an original numbers matching 77-80 Pontiac TransAm for their stable. Any thoughts on the Pontiac 400 vs the Olds 403 for whatever reason(s) future value etc.? I'm leaning toward Pontiac power because the car is a Pontiac but prefer Olds from an engine perspective.

Thanks!!!

 

T/As bring more money if they have the Pontiac engine.

 

MOST... T/As do bring more with pontiac engines..but recently, they are about the same anymore..Pontiac used the 403 because of California emissions..the pontiac 400 couldnt pass...i personally think, if its an awesome car, the motor wont matter..a ratty turd, id just leave it..nice cars bring real money now

 

My daughter bought a one owner 1979 trans am with a 403 olds motor for her first car. I did my best to get her into an oldsmobile. We originally pulled the motor to only paint it but decided to completely rebuild it to put new gaskets and check things over. The cost for parts was very reasonable and easy to find. We kept everything bone stock and numbers matching it runs pretty well and is fun to drive when she lets me get behind the wheel. She is not afraid to get her hands dirty and enjoys working on it.

Good Luck\
Scott

 

The 403 has a weak bottom-end. The main caps are bolted to Swiss cheese. GM cast huge gaping holes into the main webs of the block.

'Course, some castings of the 400 Pontiac aren't much better.

 

I had a '79 T/A with the Olds 403 in it. Red, like Sammy Hagar's Auto trans. That car would spin the tires for a block, at least; and break 'em loose again at the 2/3 shift.

 

The 6.6 T/A was one of the quickest american cars of the late 70s. Its Pontiac 400 was said to be severely underrated at 220 hp, According to NHRA its true net HP was more like 280.

Its performance backed that up, over 96 mph in the 1/4 in 1979 was very quick. That would be quick in 1969, and still quick in 1989.

A 1978 Trans Am 6.6 Litre 403CID (185 hp) hit 80 mph in the 1/4 mile. **

Take that out of the equation, if straight line performance isn't that important. Also the 6.6 T/A was manual 4 speed while the 6.6 Litre was 3 speed automatic.

**(info found without source to verify)

 

Those 77 to 79 Pontiac 400 are also the light weight blocks. All of GM was doing it for fuel economy reasons. The Pontiac experts say to not use those blocks due to a weaker bottom end. Not as bad as the 403 bottom end but still weaker than the earlier 400. I would go 403 because I know Olds better and you can buy those cars cheaper.

 

My neighbour had the exact same car, should have bought it off him.

 

Why not post the numbers for a 403 powered TA for direct comparison?

 

pontiac stockpiled and earmarked several thousand PN XX481988 blocks from the 1978 model year for use in 1979. That inventory was exhausted by May 1979, and the 400- pontiac powered Trans Am went away and the less powered olds 403 replaced it.
no 403 powered 4 speeds in 79 only the Pontiac 400 XX block could get a manual.
find me one of these Pontiac powered 4 speeds and i will gladly trade one of my Oldsmobiles.

 

Understood, i revised my previous post. Here are more detailed specs.

1978 6.6 Litre 403 = 0-60 in 9.4 seconds 1/4 mile 16.4 @ 80 mph (**)

1979 6.6 T/A 400 = 0-60 in 6.7 seconds 1/4 mile 15.3 @ 96.6 mph (Car & Driver)

**(info found without source to verify)

 

This is usually not a problem if you don't race or abuse the engine. The 403 is pretty durable if used in a normal manner.

Warren