It appears the MSD high-temp "Race" boots won't handle as much temp as their standard grey boots. This Race boot had more clearance and less than an hour run time vs. the standard boot had 200 miles.
Massaged the tube a couple mm, cut down a Moroso sleeve and edge sealed with Permatex Ultra to control fraying, with the tight clearance slipping the sleeve over the plug first made it easy fit the boot.
I know this stuff isn't rocket science but hopefully a few may benefit from it.