Ford has only used ZF transmissions for the manuals behind their diesels since 88, from 83-87 it was a T19 four speed manual. Dodge used the NV4500, then the NV5600, and GM never used a six speed, just their own version (actually two different versions, one had a very different input shaft) of the NV4500.
Ford and GM both no long offer a manual option.
I wouldn't put a 6BT into an F150, the frame is thinner and the suspension is not as strong as the F250 and F350. A 4BT fits great, though, and you can also get them set up already to fit where a 300-6 came out.