I have two threads active right now regarding some tuning issues with my vortec 383 TBI. My 91 3/4 ton, 4x4 Burb has the original ‘7060 ECM and in talking with Dave W, we’re wondering if some of my problems could be related to that ECM. It was a short-lived design and it seems that there wasn’t a huge amount of work on the hacks for it compared to the ‘7427. That and it doesn’t seem like there’s any way to get my WBO2 data fed into it due to lack of an available 0-5V input.

So one possible solution is to convert to a ‘7427, but the early 4L80e Bosch force motor requires periodic cleaning that is controlled by the ECM, whereas the later ones used a Holley force motor that did not require that from the ECM. All the threads I’ve read on this here or elsewhere point to the only solution is to physically modify the tranny to use the later force motor. Is that still the case? No way to modify the ‘7427 to take care of the cleaning? If physical mods required, how big a chore is this? Do it without dropping the tranny? I’ve also read that the early vs. late 4L80e operated at different frequencies as well, so there’s that to consider too.

Any 4L80e experts I’d love to hear from you, thanks!