early a 5 speed converson

While you are reading the above article at slantsix.org also search the forum. There are many many many ways to install a 5 speed (or even 6 speed) box into a slant powered a body. The most common/popular is the t-5 trans from a 80's era mustang. But there are other choices available. On slantsix.org do a forum search for trans swap and username "sandyinbc" he did a real good writeup on installing one into a 65 valiant several years ago, I don't believe his was a t-5 but the concept is the same.

While I do like the 833 parts are not exactly common or cheap. You can still buy a brand new WC t-5 and junkyard units are plentiful. 5 speed boxes don't give you the huge ratio drops that come with the 833 od or 833 wide ratio units.