LS Swap 70c10 Need help

[The Chainsaw]

I can tell you without a doubt that it is absolutely not true that you need a VSS sensor to avoid stalling coming to a stop. That is almost 100% IAC hold position and decay rate.

The overdrive is very nice and definitely worth it for the right price, but there aren't any tuning issues without a VSS. There are hundreds of people doing it with both stock ECU's and aftermarket. The stock ECU is a bit trickier, but not a problem with a competent tuner.