Small Block & Big Block Chevy Specific - 350vs403vs454

Well right now my 1978 trans am has a 403 in it with 170,000 miles. I was wondering what would be a better engine to replace it with?

I'm a rat motor fan so I'm biased.

You have quite a few options. More parts are becoming available for the olds motors, but most are aimed at the 455. A small or big block chevy will be the easiest way to make power usually as parts are more plentiful and cheaper than Pontiac or Oldsmobile.

Comes down to taste and what you like...

Derek

Hmm... what to choose. A plain jane 350, a 403 that makes 1/2 the power of the 350, or a BIG BLOCK 454. Man thats a tough decision. HAHA. If you got the funds, go for the big block.

i had a 403 olds in my '79 t/a. i don't remember all the details due to it being about 12yrs ago, but the mounts on the block that go to the motor mounts on the k-member can be reversed which makes an Old's 455 Big Block a direct bolt in and i even reused the very same 403 headers that were on it!!! it's the best/easiest/cheapest way to put a big block into a t/a that already has an Old's motor! and those motors are torque monsters if built right. if you're using stock casting heads, use the "C" castings, i remember being told they're the best flowing and respond the best to port work. however, i think Edelbrock is now making an aluminum head for it which would be the best way to go with a nice performer rpm air-gap if they have them for Old's.

check out the Old's Guru....Joe Mondello. he's been doing Old's motors longer than anyone.... http://www.mondellotwister.com/

I don't get it, why not drop a 455 in it? It will bolt up to the tranny, work with the shaker... or at least a decent pontiac 400...

I have nothing against chevy's, but unless you've got a complete chevy drive train that you're really attached to there doesn't seem to be much point in it...

...As stated above, I'd go with the 455 Olds. I mean, how can you beat the fact that everything just 'lines up' & bolts right in! UNLESS, you want to modify whatever motor you use to a point where the 454 Chev makes more sense because of cheaper parts.... bill

bigblock!

A pontiac should have a pontiac motor. Put a 455 or 400 pontiac motor in there. 400's are still cheap and there are several stroker kits available for them.

The 403 is a great motor too build..i did one my self for my 79. I do really recommend that you get the aluminum heads cause once you get into the 9.0 CR and above they make a lot of heat. if you need pics i'll post then too my cardomain site. My current set up is forged arias pistons .060 over, engle cam like 210/216 @.050, roller rockers, and 2.073in 1.625exh valves in ported smog head. i make around 480ft lbs torque at 2000rpm. i dont have dyno sheets yet. I keep breaking stuff. you cant beat a 4.41 bore with a 3.385 stroke ::):


The 403 is a big block. Ask Mondello.

Get a big fuckin rat :D !!

I'm about as biased as they come though on big blocks.

Get a big fuckin rat :D !!

I'm about as biased as they come though on big blocks.
heh, time to buy a chevy hemi crate motor..:D

582... :)

A pontiac should have a pontiac motor. Put a 455 or 400 pontiac motor in there. 400's are still cheap and there are several stroker kits available for them.

pontiacs can be good motors if you know what your doing with them. A local guy here in town has an 81 camaro with a 428 pontiac in it, its a mid 10 second pump gas street car. :eek2:

454 cause its just a beast

i am bias to big blocks too. 454's are easy to make good power but as redneck45 said it should have a pontiac motor. if you go witha chevy motor prepare to get crap form those poncho fans.