After many years wanting to buy a classic car I found a 1958 Oldsmobile 88 Holiday for sale I did the worst thing possible. I bought it sight unseen. Yeah, I know Stupid! The car is actually in pretty good shape but the engine is where the alarm bells are ringing because it is not original to the 58. For one thing the battery has been moved to the front of the radiator as the power steering pump sticks out to far for the battery to sit where it normally would. The valve covers are wrong and from images I have found I think I am looking at a 62' 394 engine. There is an engine block number located at the front of the engine in front of the inlet manifold 587503 and a second stamped number on the drivers side above the exhaust manifold J 200998. Is it a 62' engine? If anyone can help identify the engine i'd be a much happier man!

 

There was a recent similar discussion that may be helpful: https://classicoldsmobile.com/forums...mobile-174704/

I found a list online that says "J" is a 1963 394, 10.25:1, 330-horse 4-bbbl. (Not sure how much to trust that site.)

 

Are you sure of the 587503 ? How about a couple of pictures.

 

Thanks for taking the time to look guys.
I have a couple of pictures of the numbers I can see. The engine number is 587503. The 0 and 3 have a little damage but as you can see from the picture it not that bad.
Second image is of the plate above the exhaust manifold. Cleaning made reading it more difficult but at least the J is clear.

Hopefully this will help identify the engine.




The last number is definitely a 3

Sorry the numbers are difficult to read. I tried cleaning them and made it more difficult to read.

 

The 587503 appears to be on the intake manifold ? Cant tell from your close up picture.

 

I think you might be right about where the number appears. No other numbers are visible apart from the firing sequence.
Any ideas about the J number?

 

Look by the firewall. There should be numbers cast on the portion of the engine that attaches to the transmission.

 

Here's the numbers on a 1959 394. Yours should be a different number, but there should be something cast into the same area

 

The J XXXXXX number signifies a 1963 four barrel, high compression (10.25 to 1) engine.
But not a Starfire engine.
That info came from the 1963 Oldsmobile Service Manual.