My son and I just pulled the 400 out of his 68 a few weeks ago.
I ain't pulled a engine myself in over 30 years, actually went rather well, except we went by the service manual instructions and it said to split apart at bell housing...4 speed.. for removal.
I knew as soon as we did it that way there was no way we where going to get it back together that way.
One thing we did was we disconnected the wiring harness at the cowl and left it on the engine . Kinda figured doing it that way would make it easier routing and attaching the harness to the new engine prior to install.