I'd give the OBDI GM ECM a look.
I have one running an L28 (inline 6) in my 1973 Datsun 240Z. I have yet to find another ECM that has the capabilities that the P4 OBDI GM ECM has.
I'm running a '7749, with Code59, 3 BAR MAP, WBO2 fueling control, Boost control scaled to speed. and many other features, some planned some in alpha testing, currently I'm playing with a knock gauge output, so what ever the ECM is reading the gauge or row of LEDs (which ever type of display is connected) will show the amount of knock retard. Meth/nitrous control is also planned.
Tuning is not difficult, software is free or very small donation to get rid of the nag window when using Tuner Pro RT (
www.tunerpro.net). There are also products that will allow real time tuning while the car is being driven. These products are supplied by moates.net, there are others but seem to be less refined than moates.net products.
The actual ECMs themselves can be found cheap at wreckers, and can be had in under dash units or under hood units.
The OBD1 GM ECM also has On Board Diagnostics, limp home mode, and a lot of support through many online communities.
Linear Mode
