De Cat header pipes
Outstanding HDF Member
Joined: Sep 2010
Posts: 2,357
Likes: 8
From: Pa
I have also drilled it out. Believe the ones that have done it. It all comes out. I will post a pic of the inside tomorrow. Took about an hour to do. Like others said 16" paddle bit. I wound up burning up my 20 yr old craftsman drill in the process. Here is a pic of the inside of mine when I was done.
Last edited by pontiac69; Apr 20, 2013 at 10:58 PM.
Ultimate HDF Member
Joined: Dec 2010
Posts: 7,776
Likes: 2,252
From: wet coast BC
amazing how many times we are told by those that have not tried it that we who have done cannot do what we have done, and with such authority too.
Unless you drilled and failed keep your opinions to yourself. It should be clear that many have drilled and succeeded.
Unless you drilled and failed keep your opinions to yourself. It should be clear that many have drilled and succeeded.
Thread Starter
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Outstanding HDF Member
Joined: Jul 2011
Posts: 2,824
Likes: 153
From: Street, Md.
I have to admit I was a bit sceptical about drilling it out at first and was fully prepared to cut it open but when it started coming out in chunks after I started to drill I thought this is actually working. I guess the hardes part was to get all the little pieces out with long scraper but it came out. I wish I had a lond stiff wire wheel or something to get all the fuzzies afterwards would have been quicker.
Ultimate HDF Member
Joined: Dec 2010
Posts: 7,776
Likes: 2,252
From: wet coast BC
That and you do not want the 02 sensors to be damaged so they have to come out.
Road Master
Joined: Sep 2012
Posts: 876
Likes: 4
From: Waskom, TX
Thanks
David
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Grand HDF Member
Joined: Oct 2014
Posts: 4,190
Likes: 6,635
From: Gruene Texas
I'm gonna go a bit further on a decatted headpipe. If you look at a quality headpipe like fuelmotto, it is 2 pipes converging, and crossing over before exiting. A decatted headpipe has an empty chamber roughly 9' long, 3 1/2" round with all the horrors of crosstalk, and no back pressure. I am taking a 8" x 1 3/4" pipe, cutting a slot to taper fold it, and hammer it into the stub out of pipe visible inside the chamber, and welding everything back up. This will keep both pipes separated till the last 2 inchs before the crossover. No crosstalk, should have decent backpressure, and i'm out about 10 bucks for a piece of pipe, and mig weld.