Ok I did my 6r80 swap a little over 4 months ago . I used a v6 6r80 with 10k miles because could not find a v8 6r80. I notice the v6 case was different bolt pattern in the bell housing . I order a v8 6r80 case from ford which was $216.00 with my shop discount. My dad who has been in the transmission business for 30+ years did the case swap. I decided to use everything from the v6 unit since it was a good working unit because I wanted to see if it will work and it has been holding strong. So far I have put 3k miles and like 30+ 1/4 mile runs and no problems what so ever .