call up any company and give them your engine combo and they will send you what you need! As far as what stall ....... Thats what they get paid to figure out!!
You better off calling a transmisson place like TCI, B&M ect a company that specializes just in transmissons and convertors. That will get you a better answer
They will probally tell you to use a convertor inbetween 2000 to 3000 rpms anyway