I have a 1965 barracuda it had a transmission with 2 cables and a floor shifter . I changed the transmission to a newer one , what can i do ?

Get a console with floor shifter from a 66 and up car. Aftermarket shifters are tacky
If the OP still has his 65 seats, the 66-up console may not fit between the wide 65-earlier buckets. In 66 to go with the new console, the A body got much narrower seats