I just finished the 400E motor mount job and thought I'd add my thoughts for posterity's sake. It's a tough job - very tight quarters on the V8 - get out all your tools expect to buy some too. The passenger side wasn't that bad - I took a different approach by removing the oil filter housing. That frees up plenty of space in the front and provides an opportunity to install the redesigned check valve. I still couldn't get the top (mount to bracket) bolt loose so I too removed the bracket and mount together, brought them out towards the front, replaced the mount on the workbench, and reversed the process.

The driver's side is much tougher. I took the exhaust pipe off and still couldn't get the combination mount/bracket out of the engine compartment. So I put the bracket/mount back on the car and went back to trying to break the top bolt loose - finally got it after buying a swivel head rachet and adding a cheater bar. Then the mount alone comes out towards the rear past where the exhaust pipe was. On the driver's side you've pretty much got to figure out how to break the top bolt loose - it's too tight to get the combination bracket/mount out of the engine compartment. It still helps to take the exhaust pipe off - there's just no good access from the front. I had no trouble with the exhaust pipe, even though it was 12 years old. It's a tough project but all doable. Thanks to past contributors - I don't think I would have even tried it without this thread.