What type of transmission do i have?

I own a 1993 Ford F-150 XL. It has a 4 speed manual transmission with overdrive. But I dont know what type it is. It currently has has a 300 ci inline 6 cylinder but i want to put a 351 small block windsor in it but i need a different bellhousing. Can some one tell me what type of transmission i have so i can get the right bellhousing?