Project Muscrate

Custom headers anyone?

Here is the finished product! Final welding and a nice Ceramic coating will finish them off!

Words and photos by Jay Roeder

Hi everyone and welcome back! Things are still going at warp speed at my business (www.roederperformance
machine.com) and at home with my wife Amy and our 2-year-old son Michael, but miraculously I have been able to make steady progress on Muscrate! This article marks what I hope is a little bit of a milestone on the project. The headers are DONE! I think this was the last of the BIG jobs on the list! On to the ‘taters!
 
In the last article I promised that this month I would show what it takes to make custom headers and I am delivering! The first thing it takes, at least in my case, is no other options! I’m joking of course, but I will tell you that if I thought anyone had headers that would have actually fit I would have bought them. But, they don’t and I didn’t.

Not much room to navigate between the hedders and the inner fenderwell is there?

You see, I am using a NASCAR-style engine with Yates D3 heads, a 9-inch deck height, and custom engine mounts (plates) and locations. So, it was obvious I was going to have to fabricate my own headers. I have done this before on a tube chassis-style car and it isn’t such a big deal because you can get to everything with relative ease. However, on a car such as Muscrate with the full factory front sub frame and inner fenders, things tighten up a little bit. With a Yates-headed engine they tighten up a lot.

I had decided that I was going to build rather big headers by most standards because of the anticipated horsepower of the engine and, just as important, the RPM it will turn. I am not a “header engineer” by any stretch but I did run quite a few simulations on my engine modelingsoftware and talked to a few other HP gurus and decided that it is better to err on the large side as opposed to too small.

It seems the length of the primary tubes and, possibly even more importantly, the length and design of the collectors is more important than the diameter of the primaries as long as they aren’t too small. Opinions vary, that is mine and a few others.