8 1/4 or any Sure Grip rear for 66
Was just talking to an acquaintance today and he said he picked up an 8.25 with 3.55s and a sure grip for $250 so they are out there. He said he had to do a complete brake rebuild which added more money to his total.
I bought a 74 8.25 housing and 3.21 with a sure grip from a friend for $300. I elected not to use the drum brakes so I probably have another $300 in all new bearing, seals etc including the parts for the Grand Cherokee disc brake upgrade.