Hughes highstall convertor??,s

Hi, I want to order the 904 Hughes 3000 stall convertor,I noticed the ring gear is not on?What flex plate is needed and what size convertor?8,9or 10 inch?This will be going on a 360 with a mild cam,750d.p holley,8 3/4 with 3.91 gears.Thanks for any advise!