We're underway with our first rebuild of any type of vehicle and so far we're having a ball (by we I mean my wife and I). We have a 66 C10 and want to swap the original 283 with 3-speed manual to a 350 with a 700R4. I know I need to add a rear mount for the new transmission, but do I need to remove the current transmission mount/cross member in order to do that? I've read through a number of posts that point to the need to remove it, but I want to make darn sure before I remove a substantial part of the frame. Thanks for you help.