hey all I have an 87 NA automatic, I was wondering what would happen if you put a lightend flywheel on the 7mge slushbox? my instincts would tell me that it wouldn't work right because the computer would tell the tranny to shift at X point and that would be to low unless I always had it in power mode and stepped on the gas or it would stall out, any insight into how this would work would be very appreciated.

I suggest reading how the automatic system works. There is no flywheel on an automatic. The flexplate that engages the starter and connects the crank to converter is very thin and light.

And changing it would have no effect on the computer controls. Nor would a slightly lighter one help.