Small block motor mounts
New exhaust downpipes made
New crossmember for trans
Donor wiring harness to be converterd to work with
Wiring in power to the harness
Custom fuel setup. You can tap the tank, run a return line and get an efi inline fuel pump
as far as the wiring, dont sweat it.. Just take a look and search for ignition power, ecu power, ecu memory, fuel pump power.
Ecu power and ecu memory can be all time hot since they only pull a few millivolts..
Ignition needs to be switched, and so does fuel pump, but you can run a relay off your ignition switch to power both wires.
To make you factory tach signal work, find the pin out on the ecu for tachometer, and find signal going to the cluster on your tach and tag them together. Fuel level should be the same. Speedometer should be cable driven, so that should work. If it's electronic, im sure lokar or someone has a kit to convert it. If not, i bet dakota digital does.
Custom drivesaft possible. Could take 86 donor car input shaft, cut it and weld it to your exisiting then have it balanced.
Sounds like a fun swap. Not sure if it would be worth it for less than 200whp though.