I have an 88 Camaro that was an automatic factory fuel injected v6. Now there's a carbureted 350 in it from late 60's-late 70's and a 700r in it. The tranny is good but it doesn't have a TV cable linkage, only a computer so that's why i'm thinking it isn't shifting into 3rd. What all would I need to convert the tranny from computer operated to carburetor operated? Or what else could be my problem?