im pretty sure the hedmans require a large hole,,those pipes sweep up and then down, unlike the hooker 5208,,, you will probably have to cut 2/3 inches on the flat top side from the fire wall seem,,to the edge of the shock tower support,,then just make a shield to go on the top flat side closing up the gap,,
if your upper control are supports are rusty, i DO NOT recomend using that type of fenderwell header,, when ytou cut out enough of the inner fendwer well for clearance,with rusty control arm support,, you weaken the structure,,
i have seem them cave in,, just my 2 cents,,