Hate to start another thread ... but.. help !

Might sound like a silly question, but how is your coil mounted -- vertically, or horizontally on the intake?

We had a problem with the '83 D150 440 shop truck doing the same thing after installing an MSD setup. After a few calls to the tech department, one finally suggested moving the coil to an upright position rather than laying on its side. Apparently the cooling oil inside doesn't "go all the way to the top" and they can get hot and quit working. Bertha The Shop Truck has been running just fine ever since, and the motor change was a couple three years ago now.

Just an idea! Good luck Scott.