Editing Help with my 93 chevy trans. 4L60E

Hi i have a 93 chevy silv.four weel drive and it has a 75 build 350 crate motor and also its carbrated with an edelbrock 650 carb.and intak, No electronics! How do i get the stock trany to shift into third and overdrive. I can callum shift into 1at and 2nd but no third and fourth. Its a fully electronic tranny. What other trannys would you throw in to fix this if the stock one dont work? please email me back if you can help. sandyk_27@yahoo.com