might this be applicable to the B bodies?
https://www.kijiji.ca/v-engines-and-engine-parts/london/1968-69-pontiac-pre-heat-shroud/1423147131?enableSearchNavigationFlag=true
1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)