My truck is a '79, with the older style ignition coil (round, tube shaped, mounted on the driver's side fender, used on points type ignition systems) that came with the 20R.

The engine in it is an '81 22R, which uses the later style electronic ignition, which is supposed to have the later style square coil pack.

I just purchased the truck and haven't begun diagnosing the misfire yet. It barely runs. I don't know if it's ever run properly since the 22R was stuffed in it. All the igniton components appear to be OEM, including wires and coil. They're ancient. Assuming I test the ignition coil and find it to be faulty, can I continue using this older style coil? Or do I need to retrofit to the later style square coil?
The square coil that a 22R engine used stock is significantly more expensive than the old 20R tube-shaped coil that I currently have under the hood.

If I swap to the later style coil, what else do I need to take into consideration?

Thanks in advance for the help, folks. I know there's somebody on this particular forum who can answer my question expertly and wisely. Feel free to bust my balls in the process. I'm so used to dealing with engine codes and O2 sensor readings and other computerized shimmy sham; working on an old carbureted engine with a distributor, I feel like a retard.

 

well, I tested the 20R coil and found it to be faulty, replaced it with another of the same, and it seems to be firing the 22R just fine.