Our board vendors are great and supportive, and Highway Star is no exception. I too bought both AC Delco Ignition Module and coil from Glen.
You claimed you have 40,000 miles on the engine, is that original mileage or rebuilt mileage?
If it's original 40,000 mileage, then you might want to start in looking into replacing the timing chain, nylon cam sprocket gear, cam button and chain tensioner.
Do a search and you will find many members has replaced the nylon sprocket gear since from the factory is 25 years of age. You don't want this to break while engine is running, or it will cause major engine damage.