This is great! Hopefully this problem I'm having is something you've seen before.
I swapped engines in a 1995 K1500 4.3L 7427 PCM $OD 4L60E from Monster Transmission. Put in a 7.4L from a 1995 C3500 HD 7427 PCM $31 4l80E I only swapped the engine not the trans. or harness because I'm using the $OD mask PCM. I'm using TunerPro RT with an APU1/G1/ALD1 Several bins from TunerPro and one I adjusted from the original 4.3 memcal and these 0D_tpv5_v250.xdf A217_0D_v250.adx

My issue is that I can't seem to get correct communication with the PCM, TunerPro and APU1/ALD1. Whenever I try to open the dashboard in the .adx file I only get engine temp readings which seem accurate, TPS readings in numeric form but no gage movement, no tach (I do get tach INSIDE the truck)
Sometimes I get wild fluctuations on all the gages. The idle is very high 2000 rpm (N). ONCE I was able to see all the readings including tach AND the idle was good at 850 rpm (N) But haven't been able to recreate this. Is it possible the PCM isn't recieving certain data like tach which is keeping it from regulating idle speed? Also the IAC may be a subject of concern, I have read in some forums that when swapping from a 4.3 or SBC to a BBC, the IAC wiring needs to change but I haven't been able to get an answer on what those changes are. I have wiring diagrams from ALLDATA and they show the wire colors being the same and wired the same. But that doesn't seem to be the problem because it did work correctly that one time.

Thanks so much for this forum, any help would be appreciated.

Bobby