The 1268 kit lacks a fuel pump, also not sure you get the wideband with it either, guessing not or it’d be mentioned.

I had an early Holley projection system on a 440. It worked well enough, but didn’t have the o2 and the mpg wasn’t good. I had a truck with a TQ that ran every bit as good as that system did. Only way I’d consider efi now is with a sensor. I think the options now are cool, but being older and wiser I see them all as being more complication and small improvement for an occasional use car. Occams Razor.