Painless wiring has come up with transplant harnesses for many motors including the 4.3L in its many forms. It uses the stock ECU and if you want to use the newer Vats ECUs with your Vortec, they have a Vats diable module. Plug and play. <img src="/forums/images/graemlins/smile.gif" alt="" /> <img src="/forums/images/graemlins/wink.gif" alt="" />