I did alot of research before building the 365 vortec for my 1998 Express. It runs very well considering it is in a 6,000 lbs van. I used the factory LT4 cam not the hotcam and did the PCM tuning with my laptop. I am familiar with TBI chip burning/tuning, OBDI LT1, and LS1-edit so the vortec stuff was a no-brainer. The software/cable package was expensive though.