741 x housing

since it's 64 you'll be stuck with all 64 and earlier stuff if you want to upgrade the gears/diff.

but if you're not updating anything, no worries. i'd just throw seals and gaskets at it and roll. doctordiff has the good parts. summit and rock have the bits too, but you have to be particularly attentive to which brand (some are crap) and watch that they're not shipping from like three different warehouses and touch you up on $30 in shipping.

oh and i'll echo the sentiments upthread, the 741 is plenty strong.