[Mikey]

My 1991 is a Corey Henderson 368ci build. I have suspected serious tuning issues ever since I bought it in 2020. Made the trip from Nashville to Chicago to get it to Marc and after taking some 02 readings confirming it was rich at the lower end and down on power (too lean) at the upper end and verifying good fuel pressure we took a look at the programming and confirmed exactly what I suspected and even found the root cause of a stumble at 5500rpm that I had noticed.
Haibeck completely reprogrammed and tested multiple runs and the wide band O2 readings are great now all throughout the range. Idle is so good now that you can hardly hear the aluminum flywheel rattle anymore. Very smooth.
Looking forward to making a few passes at Beach Bend in May. Will report back compared to last time I was there. I expect to pickup 4-5mph vs previous time.
If that proves out I will officially declare Marc the best tuning wizard for the LT5. As it stands drivability is as good as my stock C6 Z06 LS7 powered car.