Engine mounts n' knocks

[Nick Benson <grayoak@holly.colostate.edu>]

A friend of mine has a '79 B that has an annoying knock that is caused by 
the rear of the catalytic converter tapping on the steering shaft.

A closer inspection also revealed that the engine mount on that side has 
evidently seen better days.

Any advice on this? 
AND, is it easy to change out one of these engine mounts?

Thanks,

Nick D. Benson
Dept. of Industrial Sciences
Colorado State University
Fort Collins  CO