65az

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

J-(Chicago)

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

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

joe_padavano

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.

65az

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?

joe_padavano

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.

65az

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.

joe_padavano

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.