I've posted this before, but it's probably buried in the Archives:
I'll assume we're discussing failures of the oil-filled cylindrical Blaster 2.
Ran one for many years, mounted horizontally, with an MSD6, recurved MP distributor.
MSD wants main power to be connected directly to battery, no ballast resistor.
Anyway, all was good until one day no start.
Tested the MSD, it failed.
Sent it to West Tech in NC & spoke with them, they asked about the coil.
Bottom line, horizontal mounting kills the oil-filled coils (vertical not so much); they were amazed I'd had it that way for many years (didn't drive the car that much).
Anyway, that created a problem in the MSD box. Basically, overheating = resistance = failure.
They fixed that and recommended the epoxy coils; the F150/302 coil = the equivalent MSD minus the red paint, at about $40 with separate dedicated pigtail from AutoZone, etc.
Also requires HEI-style coil wire, inexpensive again from AutoZone or whatever.
Not only fixed, but faster startup & cleaner running afterwards, and I've swapped out a couple of B2 coils with that setup since and highly recommend it.