Ive still got my roughly 10" long 9/16's drill bit from when I drilled my frame for a tranny mount. I put everything in first , slid the mount into place(hammered is more like it). Then got the driveshaft made for the distance. Safety glasses are highly recommended!!!
I agree with Joe.....leave the engine where it is. If you have your hood off its easy to get to everything, but once its on its a weird twist and bend to get back there to the dizzy. I like it as far forward as possible.
Did you measure diagonally from the tranny to the motor mount? You would have lost a little distance if so.