i am swapping out a 5spd tremec with a 4L65E in my 68 el Camino . Ordered a new engine wiring harness for the LS1 and trans , but the computer was flashed for a 4L60E . will this work correctly or do i have to have the computer flashed for the 4L65E? please help!!

 

You'll be fine. No difference in the two, control wise anyway. The 4L65e is the same as the 4L60e, with the exception of some improved hard parts like the 5 pin carrier vs 5he 4L60e's 4 pin.
The 65 is just a little beefier

 

thanks that was the same answer i got from the wiring harness company .