MegaSquirt (MS3) or Holley HP EFI

I’m in the planning stages of a drag and drive car for myself currently as well, and I’ll be using a turbo magnum 5.9 with a tremec T56 magnum. But mine will be blow through carbureted. I’d suggest narrowing down the hard parts of the build plan (engine, trans, diff) then decide on electronics (efi, carb, aftermarket or factory equipment) and then ask the same questions.
I have the 5.9 Magnum and Dana 60. I do have the 47RE out of the donor truck but it was a 4x4 truck and transfer case is in place of tail shaft and housing so was going to go another route. Just unsure of which transmission. There is a 904 in the car now, so to at least get it up and running will use that, but ultimately want to end up with overdrive automatic.