Duh!
So that's the Ampex you mentioned in your emails.
Cool find Xavier!
IIRC, it's Donald Lang that just got the 300 shown in the pictures I posted. His machine is without lifters (for ff or rewind) and the discussion has centered around solving this issue so far.
There was some discussion regarding the idler "donut". The condition of this part seems to be key to the performance of the transport. Not only the measurements such as diameter but also the compliance of the rubber itself needs to be within spec (being a 301 owner, I don't have to tell you this).
If you have questions regarding this item in particular, I suggest contacting Doc's pal Dave Dintenfass at Full Track (actually for any 300 part or question).
http://www.fulltrackproductions.com/Subscribing to the Ampex list should also help a great deal. Mr. Lang will surely be keeping the list abreast of his restoration of his machine and it should be really interesting (let alone all the other great stuff that gets posted there). It's been a while since I looked at them, but the list archives will also be available to you.
If you don't have the manuals, I have them. Just give me a holler.
BTW If you guys don't know, that studio photo is the band Buffalo Springfield with a couple of kids in the picture being Stephen Stills and Neil Young (and is that a young Jim Messina ?)