What did i do wrong...

Jerryhagen

Installed the distributor. I don't have timing marks on my damper anymore. Took off the valve cover to find compression stroke and a 3/4 extension to find TDC. Installed everything according to the marks. Truck will now pop on one cylinder per engine revolution when i try to start it. did i just install the dizzy 180 out?? what am i missing?

Axel-Breaker-Earl

More than likely. You should have ONE timing mark on the harmonic balancer......and degree marks on the front aluminum timing chain cover (IF your engine is a 1989 through 1993 B2600i).
You not only want to find TDC for the #1 cylinder.....but it also needs to be on the COMPRESSION STROKE. Best way to ensure this is to put your thumb over the spark plug hole as you turn the engine in it's normal rotation direction........then use a screwdriver in the spark plug hole to zero in the TDC.

Cusser

Axel-Breaker-Earl then use a screwdriver in the spark plug hole to zero in the TDC.

I would use a plastic drinking straw for this. I would definitely NOT use a pencil (folks have broken off the eraser inside the cylinder).