IMHO , I would upgrade to the '7427 PCM before doing any MPFI conversion.

I believe there is much more support and many people (including myself on 2 trucks) running it so a starting point would be easy to come by.

I don't think just going MPFI with a PCM is leaving much on the table vs TBI , granted I love the way mine run with the conversion , just thonk I could have gotten there with the TBI .

TOM