4.8L swap with TH400...VSS question

[Ackattack]

I'm finishing up my 4.8L swap into a 1990 K3500 truck that has a TH400 tranny (it was a 454). I haven't messed with the VSS wiring coming from the tranny/transfer case. Is the VSS signal needed for the ECM to control the engine correctly? If all the ECM really uses the VSS signal for is for the speedo input (in the stock 4.8L application) then I don't need it.

I know the TBI engines used the VSS signal to help with idle and some other things.

[Asylumwarp]

You need a VSS signal or you will be fighting idle/drive tables... Some people will argue you can do it, I look it as putting a bandaid on a wound that needed staples. Don't rig it.