Here is an Ebay auction for a used C5DA bellhousing by Ebay member "northeastclassicfordparts" with a starting bid of $144.99:
1965-1967 FORD MUSTANG 289CI 6 BOLT MANUAL BELL HOUSING
MAY FIT OTHER VEHICLES & YEARS; CHECK YOUR FITMENT.
DATE STAMPED 1967
157 TOOTH
THIS IS A USED ORIGINAL FORD PART. HAS BEEN CLEANED & PAINTED. HAS A BOLT HOLE THAT IS BROKEN.
SEE IMAGES FOR EXACTLY WHAT YOUR GETTING.
THANK YOU!
1965-1967 FORD MUSTANG 289CI 6 BOLT MANUAL BELL HOUSING | eBay
-Fred-