I know this is an old subject and most people are doing ls swaps these days but I’m going to ask it anyway. I have an old square body k20, a bunch of parts and want to do a tpi build in it as I have a good short block and a compete 89 tpi intake. I have read a lot on this subject including a sticky on here and understand most of the basics using a vortec dizzy and 0411 with a 01/02 express van tune. If I understand correctly I need a vortec dizzy, ignition module and coil, vortec crank sensor, express van knock sensor and a 85mm 5 wire maf. I am assuming I can use the tpi map, tps and IAC motor.

EFIconnection makes a stand alone harness for tpi with 0411 that I think would be a good starting point. It is setup for 24x with coil over plug ignition but I figure it would be easier to do a little repinning to the express van pin out and modify the harness to the vortec ignition components than to start from scratch. I found what I believe to be a good pin out for a 01 express van vin R but it doesn’t seem to have everything I need in the red and blue connectors. It also shows a C001 and C002 connector. I don’t know what these are???

Would I be better off to buy a 0411 with vats removed or get one from a express van in the yard and have the vats removed?

Is the express van throttle by wire or throttle by cable? I’m hoping to keep a cruise set up.

Some of what I have recently read references a lot of shifting and vehicle speed issues. Do I need to stick with a transfer case that has a 40 pulse vss? I believe with a right side drop that limits me to a 89-91 burb. I also read ecm needs an input for 4 low???

Any help would be greatly appreciated!

 

As far as I know The TPIs are all throttle cable types and have a separate vacuum powered cruise control module. make sure that you have a MAF (most likely) or MAP (or Both, these engines were weird) before you start buying parts, as that is the main difference between these engines between model years. The engine computers for the TPIs are really dumb (RCR's Colecovision joke is pretty spot on) and are usually just looking for a voltage range rather than actual binary data (But they are VERY picky about voltage of any kind). also remember that you can bolt a CSB carb manifold onto a TPI block with VERY little modification (or just buy an aftermarket manifold) and eliminate the ECM all together. This is what I've observed people in your situation doing as the final straw after trying to make TPI swaps work. These engines are very finicky and even in their original proper bodies they are usually a nightmare to modify. If you have your heart set on the TPI injection system, (how could you not, they have a certain charm in their quirks) then don't think performance (your not going to get high HP out of the stock manifold, just torque.), think how can you fool the ECM into thinking it's in a bone stock Camero/Firebird. (even if your hypothetical Camero isn't actually bone stock.)
(BTW I know very little about Chevy trucks, so my info may or may not apply to you.)
(EDIT: also, don't waste your time with a non-period/modern ECM. you will only find disappointment.)