The 6 speed had more HP than the Automatic. IE the 2002-3 7.3 with the 6 speed was 275hp stock, so that almost 100 HP over your 89 IDI. low milage 6 speeds 7.3's are getting hard to find. For that price, if you don't get it, it will be gone soon to someone else. And by the way, I have a...