So how do I figure out what engine I have...

403 CI.

Valve covers 350 hp, 400lb ft of torque

Left head says 4A 554 717 stamped on it

Block on the front top says 557265

 

http://oldsmobilewiki.com/index.php/...Identification

It's a small block Oldsmobile 403.
Roughly 170 horsepower in stock form.

 

Um, you mean besides this:

Are you talking about a decal that looks like this:



If so, that decal was used on the 1967 E-block 400 motor. It was never used on the 403. Someone just put it there.

 

I guess I wasnt clear, I am looking for the year of the motor, and is it a good strong motor? Are the heads any good? If the decals are not right, is it really a 403?

 

None of those decals were original to that motor, nor was the air cleaner. The block and head casting number do indicate that it's a 77-79 403 motor. Can't tell about the rest of it, since it's clearly been messed with by a previous owner.

 

Well I knew the decals were not correct.. at least some of them. Is this a good strong motor? I did see the build sheet on it, it is running a mild cam, and supposedly dyno'd at 350HP.

 

In stock form the 403 put out nowhere near 350 HP. The 403 has siamesed cylinders, unlike any other small block Olds. That level of power would require a cam, some head work, and intake and exhaust. That single plane Offy 360 intake is not one of the better aftermarket units around.