tranny blues

[eric h.]

in a 91 ford mustang gt i have a aod got from jasper stock with stock converter i recently put in a gt 40 motor basically with a 9lb powerdyne with e303 cam, my ? is sometimes when the car is driving is sometimes not always start to slip in 1 d and od , especially when the car is warmed up. when the car has been sitting for a while and you go back out to drive it it drives normal again the,it has fluid in it matter of fact it has b & m tranny fluid mixed with regular and theres plent of fluid. does anyone know what this sounds like to them could it be the fluid or stall converter or the tranny itself i need to know and thoughts cuz thinking about doing t5 conversion its my girls car and dont want to spend money if i dont have to . thanks!