has anyone used this?
Moparblood that is nothing more than a breakerless Mopar distributor mated to a GM 4 pin HEI. You can do all that yourself a LOT cheaper. Get yourself a slant breakerless distributor--came in 73 and later cars......and recurve it or have it recurved. There is a "limit plate" kit but I don't know if it works in slant distributors. Buy yourself a quality HEI module and hook it all up. Bypass the ballast resistor and you can even use your factory coil---at least for awhile
One of the great guys on here came up with this neat drawing of my "hen scratches"
BY THE WAY what are you working on as you neglected to mention. MAYBE you already have a breakerless distributor