I've read just about every thread on this subject and it makes you wonder if any of these companies really physically prototyped their designs. Could they have just taken an iron manifold, looked at a bunch of pictures and made a lot of assumptions? Header A hits a linkage, rubs a fastener or body part, header B hits the pitman arm or interferes with the steering linkage......yada, yada. I can understand the flange issues as aftermarket heads with high flowing or raised exhausts were not around when most of these headers came to the market however, to continually market a product that has known significant fitment issues says a lot about the company and you can bet they have had plenty of feedback over the years. Most of these headers are not inexpensive and to have to pour even more $$$ into them is !@#$ I recently purchased a SFI approved balancer that hit the water pump when I tried to install it. An aftermarket, stock stroke crank hit the bottom of the aftermarket piston skirts and the list goes on, as does the rant............
one of the main problems with the headman headers they are not the same from set to set ! I bought a set of Headman 351 Cleveland swap headers for a Mustang ii Chassis , one of the tubes was 3 inches to short ! My brother bought asset 1 year later expecting to have to extend the tube that went around the cross member ! when he trial fit the pipes they were all the right length but one collector was not made proper and hit the frame rail, had to be rebuilt!
Headers on our cars are a real Pain in the A**,just seems like you have to modify any set you get.I`m going to try the Hooker 6208s on my Windsor when I get to that point.They are $800 for a ceramic coated set which is expensive but to make decent HP you need them.I looked at the ones on Gary`s car (bb466) at Dinwiddie Va. about a month ago & w/ cut shock towers you only have to grind a little off the steering box(manual) & cut a notch in the passenger side frame & weld in a piece of half pipe for strength to make them fit.Inch & three qtr tubes w/ a 3in collector & they are tuned,& I know they work because his car turns right at 10 flat through mufflers w/ a 408 & a automatic.They turn down & hug the mtr pretty tight which is a good thing on our cars,GOOD LUCK to all on your endeavors.
I recently installed the Thorley's. To get around the pitman arm issue, we heated up the pipe and dimpled it in to a point in which the arm would clear. It was easier and less restrictive on the flow than having to cut and weld sections to go around it. Just a suggestion to make it work. Still sucks that they did not get it right the first time. Micah
Funny side note i bought a set long tubes from JCWhitney back in the late 80's i used them on a 74 and later a 69.5 when i swapped everything over. Wish i knew the brand now(for some reason Eagle sticks out) they were equal length tubes; both pass and driver sides went in from the top; didnt need/didnt use P/S drop bracket even though it said you would have to.... they were the cheapest i could find. the only complaint i couldnt use column shifter for the auto. Oh and one more thing If i remember the specs said they would also fit 71-73 with 351W Comet
