I dont see why a 88 5 speeds Z wouldnt work, did Jay have problem with his wiring ? :lol: Only difference could be the ac and vacuum egr AFAIK. I think he got a chip to disable the EGR anyway so the EGR is not a problem and I think he doesnt have ac, so the 88 5 speeds z24 harness should work just fine. After that, he will need to put the 2 wires and 1 wire CTS together (conversion to 3 wires CTS) for the 3400 and extend the MAP sensor wire and relocate some misc wires.
There is a large issue when using an '87 to '91 harness on a '92 to '94 J-body, and that is how a lot of the wiring is routed between the engine bay and interior.
Just to mention the wiper motor control wires on the '92 to '94 route through the passenger side bulkhead feed through, where as the earlier version were routed through the driver side feed through connector.
'92 to '94 has ABS, which has the rear axle wires routed through the driver side feed throughma nd incedentaly enough if you don't modify the wiring you will have the right rear ABD sensor connected to the wiper motor, using the older engine harness in the newer car. :lol:
You'll be much farther ahead to get a V6 harness from a '92 to '94 Sunbird, as this will pretty much drop in.