I'm looking into a set of these Ford Racing Turbo-Swirl GT40X heads for my 89 5.0. I found out I need a set of 1.60 roller rockers to make these heads work. I also found out that they make a lot of different 1.60 rockers. How do I know what ones to pick up? Why wouldn't the stock rockers work?
02 GT 5 spd. Best 1/4 12.28 @ 112mph