[DAVID GAGNARD]

5 bolt,289 blocks were very early blocks, I'm not 100% sure, but think they went to the "standard" 6 bolt block/bellhousing for the 1965 model year production........the same used through out the 289/302/351-W production until it ended.........

Don't know if any 289s came with the 164 tooth flywheel either, but 302/351-W's did, mostly in larger station wagons and trucks and they used an 11" clutch disc,vs. the standard 10.5" clutch disc......

Not sure what the original Cobras had in them,but I'd guess the early cars had 5 bolt blocks......
5 bolt blocks are hard to come by,but they do pop up every now and then.......5 bolt bellhousing and 6 bolt bellhousings ARE NOT interchangable,bellhousing type is determined by block type....

David