How do I find out what year & type olds motor I have?

 

Look for the casting number just behind the water pump (in front of the intake manifold), then check against this chart:

 

The block casting number will tell you the displacement. It will not tell you the year, since Olds used most castings for multiple years. On 1968-up blocks there is a VIN derivative stamp on the driver's side near the front. The second character of the VIN derivative is the model year.