Not sure why you'd want TeraFlex shocks but be prepared to have them blow seals and break bar pins. Are you running trimmed fenders or flat fenders? If not, you're gonna need a LOT of lift to clear 40's and there aren't too many really tall coils that'd I'd recommend being that they tend to ride pretty harsh. Of course, TeraFlex makes a set but having run them in the past, I wouldn't recommend them.