i am just about done building my 572ci Indy Maxx motor for my 63 Dart...the headers are going to be custom built and need to know what you guys think about header tube size..i have a set of 440-1(345cc)CNC'd,747/765 roller cam,14.0CR,single 1250 Dominator for now but will be installing my Tunnelram later..i didnt know if 2 1/8" is going to be enough tube or if i need to go to the 2 1/4" ??? Oh, before i forget, when i do upgrade the motor in a few seasons, i will be boring the motor to 4.5" and making 604ci at that point.. spending 1500 on a set of custom headers is something i really only want to do once..so if i go with the 2 1/4 tube now is that going to hurt me?? what are you guys using ???

I went 2 1/8 by 30 inch with a 4 inch collector, but you might go to 2 1/4 and have as good results, seeing as you have more cubes. If you are having to bend the tubes down right after the flange, might be worth going to 2 1/4. Mine go up instead of down.
Now that i reread the post, definitely 2 1/4 for the big motor. I doubt you will take much away from the 572, especially if you run a loose converter.

i haven't got as many cubes as you but i'm building my own custom headers. was up till 11.30 last nite welding these together. 2" primaries stepping up to 2 1/8" before going into 3 1/2" slip on merged collectors. they're not long tubes by anymeans & we don't have to run muffs. still have to weld on the pyro mounts & the CC extractor flare but i feel these babies when finished will help my gases flow & maybe nett me a few more ponies.

another angle. sorry pics aren't too clear. pics taken on cellphone than was getting flat

I agree with Greg. With 572 inches a 2 1/4 will fit the bill. I run 2-1/8 stepped to 2-1/4 with 557 inches. They seem to be about right for my combo.


With the cost of custom headers I wouldn't want to build them twice. I have $1300 in the headers and another $600 in collectors

i chose to go 2 1/4 x 4 for the 440-1 headed 540...thinking they'll be big enough to handle a procharger when that time comes.

If you send me a PM I cant run your engine through
my header program for you

Thanks guys for the Good Info.. Mike, I sent you a PM...

i just dyno'ed my 580" motor.the test headers were 2" to 2 1/8 with a 3 1/2" collector.then i tried my headers that i will use in the car.they are custom kooks 2 1/8 to 2 1/4 with a 4" collector.my bigger headers made the exact horsepower and 5-6 less ftlb of torque.it was a supprise to me......

Mr P-Body..here is the flow sheet you needed.. IT IS ATTACHED!!!!! the rest of the info i will have tomorrow...