Just FYI, I've taken apart at least a dozen 69/70 big block 4 speed cars, and they all had the C6OA-D bell housing ("Z" bellhousing) and they can be found dated at least thru 1970, so I'm fairly certain that that's the right bell housing for your car (99.9999% sure)
I think the C9AA-C bellhousing is for full size cars like a galaxie and has a boss and threaded hole to mount the Z bar pivot. Your car has a bracket that bolts on using the bellhousing bolts for the inner Z bar pivot. The "Z" bellhousing is fairly common but expensive as it's used on mustangs and fairlanes and is really popular, you can expect to pay 250.00 to 500.00 for the bell, block plate, and lower cover. The full size bell (C9AA-C) is a lot rarer but less in demand as there are not a lot of 4 speed 69 galaxies getting restored...
BTW, when you go to buy a bell, look it over carefully, as they tend to break around the block dowel pins, also pre 1968 bells use a pivot without a slot for the fork retainer, if you buy an earlier bell, you can either change the pivot (the newer style is repopped) but you'll see that from the outside unless you have the rivits made and are really good at riveting, or use an older fork...
Hope this helps, John
