Talk me into or out of Holley Terminator X

A properly tuned carburetor will make more power than efi because of the latent heat of vaporization of the fuel. If you make more power with efi it’s because your carb tune was off. That being said, if you don’t want to mess with it a self learning (that’s a myth really they don’t self tune they look at feedback and pick from a different table) tbi style of efi is just fine for most people. Port efi has much much, more capability and tuning options than TBI and ultimately is a better set up but you may not need all the extra features. Most of the problems with any of the efi systems come down to user installation issues (not following directions) or RFI problems which Holley has addressed by moving the ecu to the side of the throttle body. Both systems will need dedicated high pressure fuel systems (return style is always better) and if you can use your current plastic tank or not is up to you to research since you didn’t provide pictures or part numbers.