I have stayed away from saying very much on this thread, I have a 67 GTX with a 572 hemi, 735+ HP, 718 + Torque (reason for the + is that was with a 950 holly, now is a fast 2.0 EFI flows 1050) car weighs 4100 bare, lots of extras, Dana 60 w/4:30 gears, MT 12.00X30 rears, cal tracs, and of course a 855, 3400 miles on the car since the 855 went in, went thru some issues but it looks to me like you can not break it and it absolutely bolts right in, I also used a 3 1/2 " drive shaft with billet front and rear yokes. Only problem I have now is the rear wheels studs have a tendency to bend a little and they are ARP. Bottom line is this is a excellent transmission, I went thru a Keisler A41 automatic stage 3, it is no fun R&R trans to repair and have no confidence in its reliability.
Bruce