I didn't mean to be sarcastic at all but yes as others chimed in MSD distributors among others have a tendency to corrode if not maintained properly. Been many threads on the subject over the years with a crc coating of some sort to help preserve the life of them. MT posted different times the exact name of spray used. Just look under rotor and I'd be shocked if after 7 years you don't quickly identify what we're saying. Good time of year to refresh/replace some components to avoid down time during the short season we have up here.

Aluminum or cast iron heads? Be careful removing spark plugs....

Yup. Don't feel bad it's normal after a season or two.

Plugs, cap and rotor, wires on BOTH engines. 7-8 years is too long. I check plugs at the beginning of the season, and replace every other.

As others have said, look at fuel delivery on the secondary side. It might be a good idea to pull the carb apart to give the metering blocks a good cleaning. Make sure all of your grounds are good too.

I misread or didn't see the writing on post 25. Glad it wasn't yours drpete3. lol... Just a suggestion though regarding your spark plugs over and above your existing problem I would strongly suggest to change plugs and reinstall with copper anti seize. At the very least make an attempt to remove a few that are easily accessible just to make sure they'll back out ok. I've seen it go both ways in much shorter period of time. Had one come out of a friends vehicle right with the threads from the aluminum head. If run into difficulties best to work both ways left and right until out while using some penetrating spray.