Ok how can I scan for the codes since its not OBD 2?

I'm trying to read the codes on a 1995 Bonneville that's running rough. I read that you can do this by jumping the 4 and 6 pins on the OBD connector on 1995 GM cars with OBD 1.5 but there isn't a 6 pin on the connector, what pins do I jump to have it flash the codes? Here is a picture of the OBD ...

well yea that's what I want to do is make one good car with both but I'm more looking at which route would make the car worth more, what is a 66 Bonneville with a 389 worth and what is one with a 421 worth?

I have started to work on a 1966 Bonneville but I have ran into a problem so I want to know which path I should go with this restore. I have 2 1966 Bonnevilles and I want to restore one of them, I got a black color one that is in pretty good shape with a 389 Engine and a Automatic transmission with ...