Stock your 1973 CJ5 would have had either an AMC I6 or an AMC 304. The only 4 speed transmission offered in 1973 was a “close ratio” T18 and then only behind an I6 as an option. Who knows what the PO did as far as swaps. If the 8th character in the VIN is a H then your jeep came with a AMC V8 - 304; A or B = a I6 - 258, an E or F = an I6 - 232. Swaps with OEM jeep parts are easy, and we know the 360 is not stock however the transmission is most likely a T18 either the OEM unit or a swapped in T18 from another donor. The 1972 to 1978 CJ T18 transmission had the reverse over and up; only the 1979 units were over and down. From 1972 to 1979 all CJs came with a Dana 20 transfer case except for the Qudratrac CJ7s. There is not enough room in a CJ5 for an AMC V8, a T18, and a Dana 300 transfer case without making the rear drive line too short.
As far as batteries, the Optima are great batteries but with closed cells the longevity is not as good as conventional wet cells, however they can be drained by a winch over and over again without damage. If not using a winch the Optima isn’t necessary; if not using a winch buy the highest rated cold cranking amp wet cell available in the proper battery size. I use Kirkland from Costco but others are just as good.
