what we did with mine was to weld metal 2 the side's of the mount's (after u clean some rubber out)and made them solid. of course i use a auto the350 which has held up 4 11yrs. should still b strong enough 4 the stick trans. pic can b seen here
http://s42.photobucket.com/albums/e320/6pac2go/?action=view¤t=2day001.jpg&newest=1 but u have 2 look close 2 c the weld on the side. this type has been in my 67 nova since
i have had the car