I think I just scored a good score

[Clyde65]

You will need the MAF, unless you go with a speed density tune ( more expensive and needs to be Dyno tuned I believe)

When I did my truck, I did the converted stock harness, it worked fine but was really ugly and it drove me nuts. I had a performance tune done on my PCM, without a dyno, and it improved my performance alot and my mileage went from 14MPG mixed to 16MPG mixed, 20MPG highway.

A couple things you need to be aware of Mvfd70, you will need an electric fuel pump and plumb it, just a Walbro255 will be fine as long as it will supply 58psi at the rail constant. Also you can use a TH400/350 but you will need to get a different flywheel and spacer to connect. BTW a 350/400 trans will not get you the best mileage, you would need an overdrive trans for optimum MPG.