I installed Doug's headers on my car with a 428. They fit very nicely and clearance was great. My biggest beaf with them is the clearance for the oil filter and housing. I still haven't got the oil filter fit that makes me happy. No clearance at all between the filter and header. I tryed the straight housing and 45 degree housing still no luck without touching headers. I tryed a couple different style filters and still no luck. Any imput would be nice.