Barry,
moving the motor back will only raise it if it has some "dump" angle. In other words, unless the motor is angled down quite a bit, six inches of rearward movement is not going to raise it up very much. If you raise the motor (with a new mid plate) more than a very minor amount you are going to have to rotate the rear end to match. A shorty 'glide and a long driveshaft will give you a little leeway here but if the package is coupler to coupler alignment becomes more critical.
You need to add two bolts per side for the rear end mount and the outer ones need to have at least a 5" spread (center to center). Bolts need to be 7/16" diameter Grade 5 (min) and you need self locking nuts on them.
Another point---does the frame have an upright at the mid plate? Quite often when the motor is moved like this the shift does not include the addition of an upright at the new location and with a 6" move that puts a lot of load on an unsupported part of the frame rail and can cause coupler alignment problems as the frame flexes.
Roo
