I personally will never use MSD again.
There is a better unit for the same $$$. Much better quality. I had an MSD Digital 6 and had popping for years before I switched it out. Checked and changed everything. MSD checked the box twice at the track, right in front of me. Bought a new distributor even, wires, etc.
Changed the box to a Crane HI-7 and PS92 Coil.
Problem GONE..

Here is the better choice instead of a Digital 6..
http://store.summitracing.com/partdetail...mp;autoview=sku
Along with a LX92 Coil. $64.00

Just my.. See for yourself..

http://www.cranecams.com/?show=article&id=12

Also try to find a DEC 9000 or 9500 engine controller and you have a sweet set up.

Chris..