Exit1965 posted this in the General section. I was surprised.

https://www.youtube.com/watch?v=azPKIjxmmdU

Another header test video. The thing I took away from this one is how much difference in temperature ceramic coatings make.

https://www.youtube.com/watch?v=O1bXPNy1Yn4

That is totally WEIRD... granted I dont try to
smash in headers so I never tried to dyno any that
have been smashed... I figured they would show a loss
at the first bend but they proved different.. plus
they didnt make nice smooth dents, they had pretty
sharp angles which SHOULD have made it worse... I thought
it was funny when they smashed the first 2 tubes and it
made more power

I would've thought it would be down 10-15hp. It makes me wonder how that engine would respond to a smaller primary tube header.

I thought about that also.. but with the amount of
dents(how much they banged it in) I dont think it
would have mattered.. with the smaller tubes it
might have been lower across the whole run... I had
to put a small radius dent in my right side header
on my Rampage when I moved the engine to the right
by 1".. was just a small dent and I made it a soft
radius.. I built the headers and had them coated
before I moved the engine (1 tube).. so after seeing
that I am no longer worried about it

Look at surgery to the 1 7/8" TTI's it took to get them in the Rocky!

The dent is another reflective point.

Next year you will see this in summit racing for an extra $200.00

LOL... yep... the high HP version will be $200 more
with the calibrated dents/clearancing

But are they equal length😛

No.. they are off the shelve headers.. I've never seen a
off the shelve header thats equal length.. and that does
help... but after seeing that clip most will say that nothing
really matters.. but even Friburger said the diameter is still
important.. and if you noticed the length of the collectors..
they are out in the 18" range unlike a regular set of headers
that might give you 6"... that helps out torque

I still can't believe them hitting a hammer with anouther hammer, ask me how I know. AND kinking them while still on the engine. I would have had to replace at least one of those cast covers or head when it broke.

it doesn't say that they messed with the jets in the carb. you would think with the better breathing headers it might need more jet. they didn't talk about afr on each run.

The way I hear this vid is.. they built this engine
before with these headers.. assuming they tried to
make peak power they messed with jetting and timing..
then they put the engine back on the dyno(different day)
and got a base line test(first pull) then started making
changes to the headers.. no they didnt try to get BACK to
the original F/A ratios or jet to max... but in most cases
a lot of guys wouldnt on here either.. most would (if they
even dynoed the engine) would say.. the dyno numbers are
good enough... hell most wont even re-jet if they pull the
air cleaner off... at least on the vid they started with
a base line

I have never lost sleep over clearancing headers, other than paying $800 for a set and STILL needing to MAKE clearance.

I sure wondered if it hurt... but was I gonna loose
sleep over it... let me think.. NO.. but I like playing
with headers... thats why I never caved them in... hell
if I knew I could add HP I would have

im surprised my buddies chevy doesn't break the sound barrier.

so the smashed tubes on my cheap smallblock headers under the conn rod are ok? fabulous!

I ruined a new set of 2 1/8" Proparts headers I got from Mazzolini trying to get them in my Demon with the 540 / 440-1. My dents were made with a torch, air socket on an extension, and a hammer so they were nicely rounded. On the first pull to breakin the motor one of the exhaust gaskets blew on a smashed tube. The engine wouldn't get over 5500 RPM.

That SB chebby was making some good numbers and I am pretty surprised it didn't lose a bunch of power from the ex restrictions. My 540 didn't like the restrictions at all. Those headers are ruined.

The root cause problem was my motor plate that worked with the 500 and it's very nice headers is not locating the 540 where TTI wants it to be. I have now installed coil overs and no longer have torsion bars in the way.