hi! i need swap a 4l80e in my car. What year is best for the trans?

my second question, i have a flexplate for a 700r4 to fit in a ls motor,
does the flex plate made for the 4L80??

2001 and newer is the best. They have all of the "good" factory parts. They are all strong, but that is the strongest factory one.

Info from another board...

91-93 is early style. You don't want them.
94 to 96 is OK. Early lube system. Updated electronics and internal wiring harness along with case connector.
97-98 OK. New lube system.
99-00 Better. New lube system. Wide band.
2001- up Best. New lube system. Wide band. Wider planets. New overdrive arrangment.