[flowking]

Ok John, here is the real deal! There were two different sets of tools used to create headers and sidepipes. One set was for the aluminum car and one set of tools for the fiberglass car. The headers supplied to Shelby were marked with a part# of K-7110 F for fiberglass and K-7110 A for the aluminum car.
A simple way to tell if you have the correct set of headers for your paticular car is the #5 tube is a four section tube that passes over the steering shaft.The aluminum car #5 tube passes under the steering shaft. If you use the correct set for your car you do not have to beat them with a hammer!
Check the part # on the box,then check the #5 tube. There is however one caviat to this. You may have a new Shelby header which is supplied by Dynaflex which are pretty easy to spot. The tube is 18 gauge instead of 16 guage and the flanges that bolt the headers to the cylinder head are thin usually 5/16" or even 1/4" instead of 3/8".
This information is gospel and not what someone thinks they know.
Flowking