The original idea behind this project was to build a direct drop in Plug and Play solution for GM cars that used a Delphi 56 connector (86-89 TPI, 88-92 TBI). This project relies on using a Microsquirt module EFI controller with an add on stepper circuit for idle control. The stepper circuit was sold as a kit by Diyautotune, however, they dicontinued this kit a few years ago. You can source the components individually for the IAC stepper kit. I'm still using this ECU in my turbocharged 1988 Firebird formula, now powered by an LS with 58x (originally TPI). The only reason this solution is "better" than an off the shelf Microsquirt controller, was because of the additional IO available on the Microsquirt module - coupled with the IAC stepper circuit. You got wasted spark for 8 cylinders, batch fire fuel injection, fan control, iac control, a tach output to drive the factory tach/shift light, boost control via an add on circuit, and two extra 5volt inputs (pressure sensors, knock, extra wideband, etc). There was (is) no other solution in the price range that offered the same level of I/O in the mega squirt family. The links below detail the pinout jumpers required to convert your car (based on the 165 ECM wiring) to use this ECU. I originally ran an HEI distributor, then EDIS on a small block chevrolet, then finally wasted spark 58X on an LS.GM to Megasquirt swap using HEI electronic controlled distributor
GM to Megasquirt swap using EDIS coil packs on small block chevrolet
GM to Megasquirt swap using LS2 coil packs and 58X trigger on GEN 4 LSx