Have opportunity to purchase a 4l80 e transmission? Does anyone know major differences between that and the 4l60e? Gearing etc. Doing swap on 1989 Iroc to LS engine. Thanks

Much bigger ( may need tunnel mods ), strong and heaver
Same gears as a 3 spd TH400 (2.48 1st ) but with a 0.75 ration in 4th
T700/4L60/4L60E have 3.07 1st gear and a similar (0.70) 4th gear