Hi Guys, another new boy here , my first question to you all is ...
How can you visually tell the difference between a 307 and 350 olds engine ?

 

The casting number on the block between the intake manifold and the water pump.

 

Yes, I have not noticed any differences as they pretty much look the same visually.

the 307s came in quite a few cars in the late 70s and into the 80s. If it is in the 80s I think they were pretty much all 307s . . .

If the engine is in the car, often times their is a displacement sticker on the radiator top plate that will say 5.0 L (or so) Which would be a 307. The 350 would say 5.7 L.

 

Interesting , i'm about to buy a 350 ( i hope !) it's still in an "80's Delta" parts car so i can run it up but i obviously need to ensure it is a 350 before i buy.
Where exactly is the casting number and what should it be ?

Thanks

 

http://www.oldsmobilewiki.com/index.php/Category:Blocks

A 307 will have a large "5.0" cast on either side of the block, between the freeze plugs.

 

The 307 was not released until the 1980 model year, so it did not see a lot of use in the 70s.

The 350 Olds (VIN R) gasoline engine was only available through the 1980 model year. In 1981 and 82 it was only the 260 or 307. After 1982 the 307 was the only V8 gasoline engine built by Olds.