does anybody have any input on the mac headers if i get them they will be on a 89 formula with a 305 and a flowmaster american thunder exhaust and im not sure on what type of cat to use so if anybody can suggest a cat to use that would help to , thanks

 

I have never installed a set but I have seen them. I would say they are on par with SLP and Hooker (2055's). They have a great y-pipe that resembles the 2055's. They also have a slick single tube AIR set-up so it doesn't look so ugly. Mac's are rarely mentioned but they are a superior header when compaired to other brands that are made for our cars.

 

You get what you pay for. Cheaper headers typically have thinner flanges, thinner gauge primary tubes and the collector flanges (usually 3 bolt ) are thin and bend easy. Once they bend they'll never seal, and the thinner flanges will never seal on the head not to mention they're rarely a true flat surface. They've also got some quality control issues where some fit nice, while others have no fitment problems. Buy the best you can afford but never buy bottom of the barrel headers ( mac, flowtech, etc. ) Wait a little while until you can afford something better. I've seen ALL of these problems with MAC products, especially their headers.

Hooker 2460's and the Hedman shorties are almost identical, the heddman ypipe is better IMO with it's ball flanges that seal better. I've had trouble with a few sets of SLP in regards to the clearance problem with the steering shaft. Also big time rust problems, even with their coating. Horrible welds on the primaries that close off the port.

 

Mac headers are made from 16ga tubing, have a ball style flange collectors and the kit retails for $469. Perhaps their older sets had problems that you saw. There is no way these headers are in the same league as flowtechs. At least not the sets I have seen.