I was referring more to the EFI systems that came on early 90's 4.3 V6s. Specifically the port injected turbo trucks. You could go with throttle-body-injection I suppose, if staying naturally aspirated. The natrually aspirated 4.3 trucks were very common and the yards are full of them. The best ECM for boosted port-inj apps would be the 122749, which came in 87-90 Turbo 4cyl sunbirds/grand-ams, 91-92 Turbo six GMC trucks, and naturally aspirated Quad4 cars in 1988-ish. It is definitely not a one week project, and there is a learning curve involved. You'd need engine sensors from the early 90s V6 (temp, O2, Throttle Pos, knock, MAP) and an HEI disributor that fits your particular engine. You have to lock the advance weights and change the module in a typical HEI to allow computer control of the spark curve. The stock GMC truck program can adjust fuel & spark as needed up to approx 15 PSI of boost. It's just my opinion, but 8 psi on pump regular is very doable. That's an extra 100 lb/ft of torque @2800 RPM. Used ebay injectors from a late model 5.7L Camaro or Vette would be about right for fueling and you'd have two extra. As for the turbo, I'd use no smaller than the Mopar T3 Garret mentioned above, and no larger than 91-92GMC Syclone unit(MitsuTDO6/17c). Something in-between like a Thunderbird Turbo coupe T3/60 turbo would be good for a low RPM 235 truck engine. The problem with boost, is that it gives you so much power out of the box, you start wondering how much more you can have if you turn it up <grin>. That is usually limited by detonation, which has a lot to do with the quench and compression properies of the subject engine. Many Jeep guys adapt GM systems to their sixes. Because most yankee sixes aren't hi-revvers, it's the torque numbers that are most dramatically impacted by turbocharging. The GM MAP based systems gnerally do not like a lot of cam timing. They need a good idle vaccuum signal. The up-side of EFI is it is "emmisions lean" (good milage) and has good knock-retard capability, which adds to engine life for sure.
MV
