Hey guys some quick help

The Overdrive four speed was a regular A-833 with an overdriven gear set installed in place of the regular third gear. The shift lever on the side cover was flipped over to "fool" the shifter into shifting from second to fourth and then back into third, which was the overdrive gear. The overdrive gear is very small and as a result, the mainshaft journal and splined hub is smaller. You can swap OD 833 parts as a set into the correct case for the mainshaft.Slant Six owners have two bell housing options to mate G/RG blocks to 833s. The original 1964-66 Slant Six four speed bell housing is a great candidate and accepts any A-833 with a 4.35" IBR profile. These units were all cast iron. While these bell housings are becoming increasingly hard to come by, the inspection plate, dust shield, clutch fork, and fork boot can all be swapped-over from a Sixties G/RG with an A-903 three speed. The casting numbers for the early cast iron bell housings are 2463025, 2463027, and 2468431.A much cheaper and plentiful bell housing to use is the 1975-81 A-833 Overdrive Slant Six bell housing. The upshot of this bell housing is that it is cast aluminum, the downside is that it only accepts A-833s with 5.125" IBR profiles. When looking for donor vehicles in salvage yards, don't' walk past late seventies slant six three speed cars. Chrysler used the same bell housing for both A-833 Overdrives and three speeds by placing both bolt patterns on the same bell housing. A casting number for this bell housing is 3743645. (This is a 1975 number, no doubt later bell housings used other numbers.) The Overdrive bell housings use a unique clutch fork mount that you will not find on regular three speed or four speed bell housings. Make sure you keep track of the correct fork and its mounting stand that bolts inside of the bell housing!
http://www.slantsix.org/articles/4-speeds/3speed-info-swaps/3-speed-swaps.htm