I need some direction if anyone can help. I just had new motors built and installed (572 NA) in my 96' Top Gun. Everything was brand new from scratch. They installed MSD 3L's and I have burned up 4 of them in 5 hours 2 on each motor. We switched to the 2L's, same deal. I'm tired of throwing parts at it and everyone is stumped. I'm hoping the hive mind can steer me in the right direction.

Thanks

Are they wired straight to the battery? If not, probably your problem. If a decent distance from battery up the gauge of the wire.
And straight to the battery is not the battery cable at the starter that goes to the battery.

Are you using compatible coils?
There's a coil compatibility chart on the Holley site.

Yes wired to the battery, not sure how far would be considered far. I'm guessing 6-8 feet and not sure on the wire gauge. Will check with mechanic.

Will check, thanks!

They are MSD blaster coils, couldn't find the chart though.

EDIT: Found chart

https://www.holley.com/support/ignition/
Look for link "Wiring Diagrams and Tech Notes" (PDF file).

All the "Blaster" coils seem to be compatible with the 6-series boxes.

That’s got to be a new record.

Check your battery voltage. Too high (bad regulator) or too low can hurt them. Also the battery is the best and biggest filter in your electrical system.

Check the voltage difference between the direct battery feed line to the MSD box and the switched hot lead to the box from your ignition switch (can't remember the max. allowable difference..) I had a problem years ago with my '79 233 Interceptor eating boxes (not quite as often as yours) and installed a relay that supplies direct battery voltage to the box when energized by the ignition switch. Haven't had a box failure since (still carry a spare 'tho.)

Good luck- hope this helps!