OK I'll though my 2 cents in. I've probably built over 75 727s. First I agree, I wouldn't have and personally don't remove the outer low roller cam. I have put the old one back in by lining up the splines and tapping it back in w/o issue. Do replace the pump bushing. It can be done w/o a bushing driver if you are very careful by using a piece of flat material, lay it flat across and tap it in straight. Used to do it all the time before I made a bushing driver. Look carefully at the new bushing. You will see that it a rolled piece that is joined with a seam. Make sure the seam is not inline with the area where it will be staked. Round an old punch or hinge pin and stake it. Remove the slight burr with knife, check it now on the converter to make sure it slides on freely. You 2 springs in the front servo. make sure the front clutch drum takes 4 frictions. If it;s set up for 3 replace it, they're cheap Clean the governor. Other than that the most difficult task is installing the front drum piston. You can't rotate it or see the outer seal. take a large zip tie , go around the seal and put the piston/seal/zip tie in the freezer for about 15 minutes. Take it out remove the zip tie , lube the seal and set the piston down as far as you can get it w/o forcing the seal to roll outward. You can fell when this happens. Then take the drum in your hands and tap it hard against a 4x4 wood block. the piston should fall down into the drum. If it does't work. try try again. Do not force it. When done drop both the input and drums into the 'front pump and air check it. Now's the time, don't wait until it's already assembled. I taught myself over 25 years ago. Pay attention, go slow. It will work fine. For what it's worth I run the original 1965 low roller in my 64 Belvedere. 200 passes it looks like new. The car ran 9.18@146 last weekend.
Doug