Header Design Using Dynomation 6.03.12 With Wave Action Analysis


Staff member
Well, I have them but was waiting until I had the car running. I can go ahead it's no problem.

The construction and welding is very nicely done. They fit well and don't even come close to hitting
the front suspension rods. I was also worried about the turnout hitting the rear suspension hairpin
mount, but absolutely no problems there.

I did have problems with the flange fitting over the ARP studs. I ended up drilling 5 of the flange holes
to 27/64" and one hole to 7/16". You might remember that I had Time-Serts installed in all the holes
and was told by the machinist that he locates the holes based on dimensions and not by locating off
the holes that are already there. So I hope that the studs are very accurately located and the flange if
accurate would fit on without trouble. But I cannot prove that my studs are NOT the problem. When I
asked Zach about this, he said that he bolted them up to and engine there in the shop. I checked the
one image from them (shown above) and it does not have bolts in all the holes, but maybe he did later.

The other disappointing outcome is the header ports don't match the exhaust ports in the head. I
thought that was the point of making those copper header gaskets and making them fit precisely and
then sending those to GP Headers. But when I asked about that, Zach said it was to make sure the
header ports were larger than the port in the head and did not hang over into the port at some point.
Since I don't deal with this type thing every day, I'm not sure if my expectations were too high. I never
asked the right question to exactly tie that point down.

They didn't send my copper gaskets back with the headers. So when I called I also asked for my PVC
back that was addition to their kit. They still had not broken down my mockup yet, but would do that
and get it out in a couple of days. So when I did not get the gaskets and PVC in three days I emailed
them. They got back with me saying that my stuff went to the wrong address, but they had talked to
the person that did get the gaskets and they are sending them to me.

So at this point I'm still waiting on my copper header gaskets to arrive.

Last edited:


The Grumpy Grease Monkey mechanical engineer.
Staff member
yes they do look well engineered and well fabricated, congrats


Staff member
Early Monday morning I got a call from Zach at GP Headers.

He said that he would rather do this in a phone instead of emailing back and forth. He still maintains
that he bolted the headers up to a SBC. But he also said that I paid a lot of money and the headers
should be perfect. He wanted to know what I wanted. Well there is not much they can do, unless I'm
willing to send them back and wait several weeks. That still would not guaranty that the flanges would
fit. At least they did offer to make it right.

I did find out what happened to my copper gaskets. There was two boxes and the labels got switched, so
it looks like I got a free T-Shirt. But I would rather of had my gaskets, the weather is too nice not to have
the car running and cruising.

While waiting I needed to do something ..... oh yes the sharps edges. I used my die grinder with a
unitized wheel to remove the razor sharp edges on both the inside and outside edges.


Also while I'm waiting, the radiator looked like it might be leaking from looking at a couple of places that are
showing a trail of contaminants or it could just be some coolant that I spilled. I took it to Osborn Radiator
shop where I take everything cooling related and had it pressure tested. There was no leaks, I asked him how
much I owed and he said nothing. COOL !!!


The Grumpy Grease Monkey mechanical engineer.
Staff member
Id love to hear your impression, of driving with the new headers,
once you get a test drive, any chance of that?


Staff member
Not a problem, but let me spend some time with them before I give an opinion. I've only driven the
car a couple of times and I can't go WOT just any place.
Last edited:


The Grumpy Grease Monkey mechanical engineer.
Staff member
yeah, when I was driving my 1968 corvette with side exhaust and crower injector stacks sticking out of the hood,
I was frequently followed by a police cruiser , that would appear within 20 -30 minutes ,
of me starting to drive around, who would follow me like a puppy ,
that assumed I had a pocket full of bacon strips to hand out!

who invariably felt it was just a matter of minutes,
before he would have the opportunity to ticket me for excessive speed ETC.
so he could fill his quota.

I learned fast to drive 2-3 mph under the speed limit,
stop at all stop signs for 7-8 seconds,
start without spinning tires
(that could be difficult on sand/gravel/ wet roads)

not my 1968 vette but it looked rather similar
Last edited:


Staff member
Today I noticed that ALL the exhaust ports are leaking, the middle two cylinder a little more than
the others. I've tightened the ARP studs and rechecked them again to make sure they are still tight,
no change.

The material is C110 copper and is used for automotive gaskets if you believe the place where I
bought the copper.


Copper C110
Typical Applications: Architecture: Skylight frames, roofing, building fronts, flashing, gutters,
spouting, downspouts; Automotive: gaskets, radiators; Builders Hardware: butts, tacks, nails,
soldering copper, rivets, cotter pins, ball floats; Screening, wire screening;


My next step is to try Annealing the copper. That means bringing it to a temperature between 700°F and
1200°F, then letting it air cool. Will let you know when I know if it works !


Step #4
Keep the flame focused on the copper until it turns red.
As you continue to heat the surface of the copper with
your acetylene torch, it will turn black. Don't worry that you're burning the copper yet; it must turn
black before it turns red.
Continue moving the torch over the surface of the copper until the black color turns into
a bright, glowing red. At this point, the copper is annealed.
  • Regardless of the size or thickness of the copper you're annealing, it will be fully annealed once it's glowing red.
  • Copper that is glowing cherry red is at the correct temperature for annealing purposes.


Staff member
I was reminded that I never gave my impression of how the headers performed and
sounded. First off the copper gaskets have sealed very nicely after being annealed. That
really did the trick !

Performance wise has improved in the bottom end, I'm really having to be aware of the
wheel spin so I don't over rev the engine again in 1st gear. Second gear is a hand full
when it shifts, it can still get sideways and with the short wheelbase it always exciting to
see if I can catch it or do I back out of it. So I'm really enjoying the extra power !

Sound is nice and have gotten compliments on the sound. But I will let you be the judge.
The collector is short and it's tapered, so it hard to keep a baffle in there. Even thou in the
2nd video I show a test with a baffle, I only ran them for a short time. They would not stay
in the tapered collect. So far I've never been stopped for running open headers.

In the first video below:
During the 1st pass I bumped the shifter into 3rd gear from Drive, this took my attention
away from driving and the reason why the car changes lanes, I was looking down briefly!
I'm trying to leave it in Drive and see where the new transmission governor shifts. If you
watch thru the steering wheel, the Tach is on the left and straight up is 6000 rpm, I finally
had to lift so the trans would shift, I think it was about 6300-6500 rpm. I'm wanting it to
shift at 6000 rpm. On the right of the Tach is the Speedometer and straight up is 70 mph.
Not sure how much you can tell with the camera bouncing around.

On launch you hear some tire spin, but then it goes away because I am feathering the
throttle. I'm trying not to over rev the engine and bend another intake valve which has
already happened once.

Last edited:


The Grumpy Grease Monkey mechanical engineer.
Staff member
with baffle and no packing sounds the worst,
the open headers sounds OK,
and with packing and baffles sounds ok, but restricted/ choked