I just swapped out my hedmans from the year 2000 on my 76 F-150 390 4x4... Rusted thru 5 -6 (North East Weather) years ago and the truck has sat since...(from me being overseas)... Just installed Hooker 6906 HKR - Holley Performance Products Ford F-100/F-150/(4WD): 352-390*6906HKR (note - the picture is deceptive - they do come with 2 1/2" 3 Bolt Flanges welded on - and no collector reducers included)... Got em from Amazon.com of all places... Cheapest price I could find plus free shipping.... Took a few weeks to get them, but I'm in no rush.... They slide in a little easier than the hedmans I had... I also wanted a thicker tube wall 16 gauge vs 18.... Although the the exit locations are different .... but so are the new hedmans - they switched to a ball and socket flange style collector meaning I had to cut up pipes anyways..... BEWARE --- ON EITHER BRAND OF HEADER --- you will have to remove the starter and lift the Passenger side of the engine up to get the header on that side in... I also lifted the drivers side to ease installation..... The tech guys at Hooker told me that the Cheaper Flowtechs may fit 4 or 5 or 6 applications where as Hookers fit only 1 or 2.......