i have srod 4-speed still in my 87 5.0 ,thats the way it came, havent got around to c-4 conversion yet . there are 2 versions of this
trans 1 weak other medium , take off
trans top cover ,mainshaft gears will be either 1/2 inch(weak) or 3/4 wide(medium).i have driven mine for 2 yrs off and on , never abused it but got on it at least once a week still works good.do not buy used
trans without removing top cover and reallly inspectig gears. t-5 or srod.fixing t-5 insnt cheap.you dont want to pay 300$ for t-5 and then have to pay 400-500$ for overhaul.