Sniper EFI and ignition type

I was going to suggest you consider using a GM HEI module which would be very similar to using Mopar ECU

On a side note I still have one of those MSD 5300 series units, which I used to run on my beat up SB Mopar swapped Landcruiser. The hood leaked like a sieve, and you'd get snow/ water/ mud up from underneath, so I mounted the box and coil on the inside of the firewall and ran the coil and trigger wires out through grommets in the firewall.

Part of this was "inspired" because earlier, using a Mopar box, I got enough dirt and water up under there that it missed and ran poorly BECAUSE IT GOT DIRTY CONDUCTIVE WATER all over the "hot" (electrically hot) transistor on the box!!!