First of all, thanks to this site for great info about doing the LS1 swap into a third gen Firebird! I did it mostly by myself guided by info here and it works great! Car is a red 1990 Firebird T-top that had the V6. LS1 is from a 2000 Camaro with 110K miles, from a local junk parts dealer.

Sinister Performance from Indiana was telling me that he could change the Cruise shift table to performance figures so that i could select by toggle switch to use the normal shift table or performance. That sounded intriguing to me since I was shifting manually (4L60E) to avoid wheel slip on launch when drag racing. (Otherwise it would shift to second too soon without WOT). The switch only has to ground pin 13 on red PCM plug and computer chooses the cruise shift table, and every shift is custom configured. Easy! And it works great. I just used another switch on my small N2O control panel.

Next I need to add posi to axle and get a lower ratio. Always something! Good luck!

 

Have new axle ordered from Rockauto.com This will have 3.73 gears and posi! This should reduce the experience of being left at the line by many cars in our local drag competition.
The LS1 sure likes the long headers, three inch exhaust pipe and Hooker high-flow muffler. She has a mean roar!