Head pipe to manifold flanges

Probably worth ordering complete front pipes if they are available for your combination of manifolds and body with whatever tubesize you want.
If you want to build your own exhaust im sure you can have any muffler shop make a short piece of tubing with just the correct flange and type of flare for you to make a start. I used to work with that and its not realy rocketscience to start with a straight piece of 2½" OD tubing(or2 1/4" od if the first bend after will get real close since it will be easier to slip the next piece of 2 ½ tubing over it and then just tap it lightly with a hamer to get a tight fit to weld up, real easy) and decrease it to 2"(or whatever OD size needed),slip on a flange and then make a flare or femaleballjoint,takes less than a minute,if you havent already installed the manifolds you can bring them to the exhaust shop to make sure you get the right conection.

Darn i just made something very simple sound a whole lot more complex than it realy is.:(