Can someone tell me what year block this is? Here are the numbers. But the block does have J heads on it also. Earlier block with later heads?

 

It's a 1969. The first digit 3 is for Oldsmobile division. The second digit 9 is the year. The letter following that is the assembly plant where the car was built.

 

Great. Thanks..
Now I’m just curious as to why somebody would put J heads on that motor.

 

If you decide to change them create a parts wanted post. Also include your location or nearby big city. Shipping costs might be a factor depending on how far they would need to be shipped. John

 

The "X" in the third position of the VIN derivative stamp is the Fairfax, KS assembly plant. Fairfax built Delta 88s for the 1969 model year. By the 1980s, "J" heads were the only factory replacements available from the parts network.

 

Thanks, great info..