plus in 1990 your tranny should be a 700R4. making this swap super easy, basically all you need is
-Holley ByPass Regulator (http://www.summitracing.com/parts/HLY-12-803BP/
) Has to be bypass if you plan to keep the TBI Pump.
-I would recommend a HEI Distributor
Steal the 12V for the Distributor from the Pink wire in the stock coil harness. '
Keep the CTS, VSS, OPS so your gauges work.