LS swap for my 75

[Zoomad75]

Bruiser- We had talks about an 8.1. Fact was the engine that is in the polar bear came from my garage. My budget really wasn't jiving with the expense, harness and controller, ect. So we horse traded and I got the MEFI4 controller and custom harness to run the 5.3 on, he got the engine. Hindsight being 20/20 knowing what I've spent so far on the 5.3 the 8.1 swap might be a wash. Then again my 5.3 was a take out of a customer's truck that had us install a 5.3ho GM performance crate. So no cost out as he didn't want it. Mine has room to grow with the 5.3 though as a 6.0 isn't hard to find either.

Getting back on track, if the OP is planning on using the PCM and wiring from the donor truck, using a 208 isn't going to get the vss signal needed. Go look for a pass side drop 241 from a 90-91 Blazer or Suburban. Specifically, a 27 spline input to match the 4L60e. That will have the correct VSS tone ring and sensor on the output of the t-case to provide the input needed to the PCM. The 241 will bolt right up to the 4L60e too.