Interesting idea on the motor mount stuffing - I definitely will try that one
for my Tiico.  As for the exhaust mounts, I made my own using 1/8" iron flat
stock, 3" wide, and bent it over double around a 1/8" by 1/2" strap.  The
strap ends were turned up and holes drilled to accept a bolt to tighten them
around the exhaust.  I drilled appropriate holes and cranked it down.  It has
been the only thing that has lasted so far.  No welding, either, just bent in
a vise and hammered flat.
Good luck

Bill Marshall
85 GL/Tiico
PHX AZ