Exhaust Cutouts

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I installed a pair of cutouts in the exhaust system of my 1969 Firebird last weekend.I started out with my TA Performance 3" exhaust, to which I added an H-pipe last year.  The crossover really helped to keep the noise level down, which was the goal in the first place.The exhaust system as I started (this picture is actually from last year):I completely removed the exhaust system from the car because it sits fairly close to the floor and I didn't really trust myself to do the work from underneath with the car up on jackstands.I started by welding a couple of braces to keep the system aligned as I cut it into little pieces.  I then marked and cut out a section for installing the first cutout, and chopped off half of the "H" so that I could attach it to the cutout.Fitting the H-section to the cutout turned out to be the biggest pain.  Basically lots of grinding and shaping to get a good fit.  After I had it the way I wanted it, I traced the outline of the fishmouth, drilled a hole with a 2" holesaw, and ground the hole to size/shape using a carbide burr on a die grinder.I did the work in halves to make sure everything stayed in alignment as much as possible.  Here's a shot after the first side was done:The 1x square sections are scrap metal that I used as braces.A shot of the nearly straight shot out the cutout:The other side went exactly the same, except the H-section decided to be a real bitch.Now, if I'm lucky, it'll still bolt up to the headers when I get the motor back in the car.Total cost was around $60 for the two cutouts.  Time invested was about 4 hours, including beating the system off the car with a mallet.When I was done I painted the whole thing with Krylon BBQ paint:It's drying in those pictures which is why it's blotchy.The welding was interesting.. both the cutouts and the exhaust system are 16awg.  I think the exhaust system is aluminized.  I sanded it down to shinyness with a Roloc disc but it still wanted to burn through.  I had to move REALLY quick and the end weld actually turned out very nice looking and pretty flat all things considered.  I'm still getting used to working on round stuff--it's difficult to keep an even amount of stickout as you move your way around the tubing.   There are a couple of spots where I screwed the pooch to some degree and ended up with the bead a little higher than elsewhere, and some spots where I had to fill holes that I had burned through, but at least I think I've finally got the hang of restarts.Overall for exhaust welds I'd say they look pretty good
Reply:nice job, lets see the CAR, BRIAN
Reply:Here's a video of the car at LACR last year:http://www.offline.org/~burch/videos/pdd/tt1.mpgLACR is around 2700' elevation.  The car has run 11.20s@122mph at sea level.  Hoping to be well into the 10's with the cutouts, traction, and a new torque converter.There are hundreds of additional pictures at:http://www.offline.org/~burch/firebird/
Reply:G.D. man that is one sweet car almost looks like a sleeper besides the cage, neat color  god that is one nice car !!!!!! are you cgoing to make the hood functional ? good luck brian
Reply:Well, technically the hood's already functional, as the stock hood wouldn't even close over the motor. My wife has been itching to cut the scoops open with her RotoZip--I've been holding off because I didn't want them open without an air cleaner but I think I've finally found one that will clear.I guess you could consider the car a sleeper--if you were deaf.  Here's a video where you can hear the engine/exhaust pretty well:http://www.offline.org/~burch/videos/firebird.mpgThat's through the mufflers, BTW.
Reply:Oh, another related project that you might be interested in was the headers.I'm running 2" primaries with 3.5" collectors.  Due to the unique nature of my car the out of the box headers I bought wouldn't work.Here's a picture of the headers as they started:And here's what they looked like when I was done:There are lots more pictures at http://www.offline.org/~burch/firebird/headers/At the time all I had for welding equipment was a ARCWELD/Lincoln 115V welder, and I didn't trust my welding skills enough to do the job myself, so I just tacked the pieces together and had my father-in-law TIG weld them at his shop.I originally just wanted to pay someone else to do the work for me but I got price quotes in the $2500-3000 range with a month or more lead time.  Just crazy.  The job took me a full weekend and I've been extremely pleased with the results.
Reply:nice job man, thanks for the photos, gotta get a little mig.... miller 135 will do the trick. you will be amazed that youve gone this far with out one,brian
Reply:Very nice work and car - I have a question on the headers:  I have seen designs for what I would describe as a subcollector, where two ports on each side run into a "Y" then those two run into the collectors.  Do you see any benefit to that design over running all four into a single collector.  I want to "improve" a 460 gasser in a truck and may build my own set of headers.
Reply:Originally posted by HWooldridge Very nice work and car - I have a question on the headers:  I have seen designs for what I would describe as a subcollector, where two ports on each side run into a "Y" then those two run into the collectors.  Do you see any benefit to that design over running all four into a single collector.  I want to "improve" a 460 gasser in a truck and may build my own set of headers.
Reply:Originally posted by arcdawg nice job man, thanks for the photos, gotta get a little mig.... miller 135 will do the trick. you will be amazed that youve gone this far with out one,brian
Reply:For the rollbar my father-in-law brought up an industrial MIG welder from his shop.  I'm not sure of the brand but it had a separate CV power supply and wire feeder.Some pictures of the rollbar installation--my father-in-law did all the welding on this.  We used a Competition Engineering mild steel kit--NHRA requires TIG welding on chromoly roll bars/cages and the cost for a chromoly kit was roughly twice that of mild steel.
Reply:john check out ASK ANDY   on the miller site it more auto relaited you will enjoy it , looking foreword to seeing you over there brian