What year if at all did chevy use a vehicle speed sensor (v.s.s.) with a speedometer cable all in one unit.I need to tell the ECM vehicle speed so the idle air control (IAC) will reset itself. running a turbo350 not the 4l60e thats suppose to be with this ECM.Or does anyone make such a thing so I can run a speede cable and the V.S.S. off the transfercase.I hope this all makes senes.:confused:

Take a look at www.jagsthatrun.com/ maybe able to help you with VSS.

What year if at all did chevy use a vehicle speed sensor (v.s.s.) with a speedometer cable all in one unit.I need to tell the ECM vehicle speed so the idle air control (IAC) will reset itself. running a turbo350 not the 4l60e thats suppose to be with this ECM.Or does anyone make such a thing so I can run a speede cable and the V.S.S. off the transfercase.I hope this all makes senes.:confused:

There's lots of options avail.
I currently run a JTR VSS but I have also ran a simple cruisecontol VSS that you put a magnet on the driveshaft like the audiovox CCS100.
It also works perfect and they are cheap.

There used to be some inline ones on ebay for less then $5. But I haven't seen them in a while.