Well thanks for the comments. Someone else warned me about Pro-Jection too, and said Howell's is good, but it's over $1000. I think at this point I'm going to buy used Weber 32/36 DGEV (around $200) and run that, and get on the road, and keep this is a project for later.
I will look at MegaSquirt again, it's probably the right way to go, though it's more involved. I can probably work out a nice subset of it for TBI, but probably not this year.
A: I have to say their customer support totally lacks. One of our customers spent $5,000 on Holley stuff, but when he tried to get tech support, they ignored him for 3 months, so he just returned it all new in the box! (Can you say ouch?) You'd be far better off with the GM TBI setup which has LOTS of support online and by phone. 670 would be great for racing, but would suck at the pump and idling the Pro-Jection system tends to overfuel no matter where you set it. That's been the experience of many with the V8 setup at least till they got the O2 sensor setup and plugged off all the AIR system. (Cam Brown's Flying Eagle did that as well as Don Hansen of the FSJ list and Garrison St Clair {MHRIP} of the strokers list in Mexico) Others poke and prod and keep tweaking the system and change the MAP programs to match what they need from it. (Several suffered total system failure during
the Ouray FSJ Invasion of '02)