chevy or pontiac

[ace]

Hi,
A 1968 firebird
looking at the the engine is there a way to tell if it's a chevy or pontiac 400 engine? Also the speedometor is off I think there the wrong size tires (14" rims) on it any idea what size the correct size?

thx's
Ace

[N20LT4Bird]

If its the original engine - its a pontiac. If not the original, the pontiac is larger in appearance, the valley pan can be seen through the intake manifold ports and the water pump is partially bolted to the intake manifold. I'll see if I can dig up a picture of a pontiac, I will post it.

The original rim size is 14".

[wolfdogs]

i think they were a diff color back then too....cant remember..but redish orange for chev, green for poncho...or blueish green????????

[N20LT4Bird]

in 68, the pontiac was a silverish blue color. heres a pic.

[N20LT4Bird]

heres another pontiac.

[Joe 1320]

Many times engines are repaited to non stock colors. The easist way to visually tell the difference between a chevy and a pontiac motor is by the exhaust manifold. The chevy exhaust ports come straight out the side of the head 90º from the mounting flange. Pontiac exits in a more downward direction, almost pointing at the motor mount, close to a 45º downward angle.

[ace]

chevy or pontiac

It' blue and the exh. manifolds are at a 45 degree angle. It a pontiac.

thank's

Ace

[N20LT4Bird]

Take a look at the head casting number. The power that your pontiac is making depends alot on the heads you are running. Look at the middle exhaust ports- its stamped right on there. Let me know what you've got.