You are about to see what I believe are the very first pair of ultimate performance headers for a 346 cubic inch LS1 due to the true equal length design, stepped primary tubes and welded-in merge collectors w/dual O2 sensors!

It took me about 5-1/2 days to do all of the "cutting & pasting" with my tube cutter & MIG welder (plus deburring all edges) to fit-up all of the tubes in the chassis and ~10 hours of TIG welding by my brother-in-law to complete these babies and I must say for my very first header building effort they are absolutely awesome <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Here are the header technical spec's:
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• <font size="2" face="Verdana, Helvetica, sans-serif">32" overall primary length</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">the first 12" are 1-3/4" 16 gauge mild steel tubing</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">balance of tubing is 20" long 18 gauge 1-7/8" mild steel tubing</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">merge collectors neck down to 2-3/4" OD with 3-1/2" OD outlets</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">two welded in O2 bungs (one for primary O2 sensor and one for Wide Band O2 dyno use so it will normally be plugged)</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">stock LS1 A.I.R. fittings welded in place</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">0.400" thick header flanges from PACE</font></li>
• <font size="2" face="Verdana, Helvetica, sans-serif">0.375" thick 4 bolt 3-1/2" diameter collector flanges (custom cut on an Abrasive Water Jet)
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<font size="2" face="Verdana, Helvetica, sans-serif">Here are a couple of pic's prior to sending them out today for Jet-Hot 2000 coating:
<img src="http://home.earthlink.net/~bzdel/ls1lshdrunf.jpg" alt=" - " /> <img src="http://home.earthlink.net/~bzdel/ls1rshdrunf.jpg" alt=" - " />
I specifically designed these headers to fit my '88 Monte Carlo SS chassis (and they clear everything!) and based the specifications on what my 346 cu. in. emissions legal motor configuration with the B1 cam, LS6 intake, ported TB & fully ported stage II heads (est. ~475+ FWHP).

The balance of my exhaust system will consist of 3-1/2" duals entering Dr Gas "X" pipe (3-1/2" in, 3" out) and exiting into 3" dia true duals w/DynoMax Super Turbo mufflers to keep it a sleeper. I will also use an extra pair of flanges to bolt in my Carsound 94009 3" CATs strickly for emissions testing and then replace them with a straight 3-1/2" dia. pipe for daily use.

Unfortunately based on turn around time I won't get them back from Jet-Hot for about 3 weeks <img border="0" alt="[whiner]" title="" src="graemlins/gr_cry.gif" />

And yes, Dyno results will be forthcoming before the stage II heads go on....enjoy <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

P.S. Total cost, less Jet-Hot coating ~$780 ($420 for parts, $200 welding labor & $160 TIG/gas rental + $0 for my time <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" /> )

 

Great looking set of headers, got a couple of questions. Why did you go with stepped headers instead of straight tube? Any reason you went with TIG instead of MIG for the final weld other than it make a much nicer looking weld? Why did you include AIR? You must have included AIR in your swap how did you accomplish that with the Fbody electric AIR pump in your swap?

 

Thanks fbird_ta! Stepped for more power & torque, TIG for appearance & A.I.R. just in case the smog ****'s get picky a few years down the road and pop up the hood on my car while emissions testing. I do not have it functioning.

 

Your welcome John. In case your wondering I have sent you a few emails directly with LS1 swap questions. Great job with the Monte! See my signature for more info. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
I've heard different reports on stepped headers vs. straight tube. Looking forward to the Dyno / Track results! Then I will be able to build the second most ultimate LS1 headers.
Still thinking about MIG and a grinder. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

^Oopps forgot the Signature

<small>[ June 19, 2002, 11:44 PM: Message edited by: fbird_ta ]</small>

 

aren't you afraid of some exhaust problems with a big collector and DOWNSIZING it?

 

Good work! I was wondering if some of the folks doing LS1 swaps were going to do this.

 

Those are beautiful headers john! Looks like you copied my setup <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> I think you wont see the full gain for those headers while running 3.5" collectors at stock cubes. I know that one 400+ rwhp cam-only car lost about 5 horse when he swapped his straight grotyohanns out for stepped dynatechs with 3.5" merge collectors...

Two big thumbs up for the crafstmanship! Those are going to look great after you get them back from Jet-Hot <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Holy Christ, they look like Pro Stock Headers! Great Job!

 

Those are the BEST looking Monte Carlo LS1 headers I've ever seen <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Tony

 

Dem Purty! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Glad to see you finally got those designed and built John. What made you decide on 32"? I remember some long discussions on what the proper length might be.

 

Those look great! Cant wait to see themin the monte out at Bremerton or PR!

 

Thanks all for the positive feedback everyone, you're awesome <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

JimmyKash, when you say </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">aren't you afraid of some exhaust problems with a big collector and DOWNSIZING it?</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">what possible concerns should I have? I had two independent header design companies run the numbers in addition to my back of the envelope calc's and we're all insync <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> As for downsizing from 3-1/2" to 3" I would hardly consider this a dramatic reduction. As the exhaust gases cool and the velocity slows the size doesn't need to be as large so this is why they downsize after the "X" pipe.

TrahnZam WS6, as for your statement </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">I think you wont see the full gain for those headers while running 3.5" collectors at stock cubes. I know that one 400+ rwhp cam-only car lost about 5 horse when he swapped his straight grotyohanns out for stepped dynatechs with 3.5" merge collectors</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I would concur wholeheartedly with your statement and add that I expect to gain it back and then some with the addition of fully ported S2 heads since this is what I used for my design criteria. Good call!

Chris Spiess, I didn't decide on 32" primary length, this is what the calculations drove out based on my projected engine torque, head flow, cam specs and desired optimum RPM operating range was.

If my plan was to make this a "race only" vehicle or try to optimize it for drag racing with sticky tires the recomendations that I received actually stated to make a triple stepped header starting with 1-5/8" primary tubing <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> I wanted to trade off some of the low end potential for top end since I can already boil the tires at will on the street with my stock exhaust & heads and I don't plan to spend a lot of time at the track with sticky tires.

 

nice work.

steve frank

 

Very nice work!! <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

 

Looks great. Want to build me a set of titanium true 1 7/8 drag headers without emissions fittings? Or how about made of inconel?

LOL I'd love to have either.

<small>[ June 24, 2002, 04:57 PM: Message edited by: The Derek H ]</small>

 

Good god! Those are beautiful! Awesome work bro. Planning on making any for the Fbods? I'd be in for some Jet Hotted 1.75"ers..... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

 

Very nice craftsmanship <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Thanks again all for the positive feedback <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

The Derek H, if you could afford Titanium or Inconel headers you should be using a C5R block & heads to boot <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

Diesel, I hadn't thought about making F-body ones due to cost vs. benefit. I honestly believe that with the current offering from Hooker on their 1-3/4" LT's that for the potential 1 to 4HP increase by having all equal length stepped tubes like mine just couldn't justify the cost. Same story with the merge collectors. When you take it as a package (stepped vs. same diameter plus the merge collectors) I am hopeful of 6-8HP over the standard 1-3/4" primary design w/o merge collectors on my all out H&C 346 emissions motor. If you wanted something close at a reasonable cost, just add the merge collectors to the Hookers IMHO. Good luck!

 

Hey John,

Beautiful work!!! As a fellow header manufacturer <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> , I really appreciate how nice your headers turned out. Of all the various fabrications I've done on my Chevy II, I enjoyed making headers the most. There is something kind of cool about routing all those tubes and getting them to turn out the same length and not hit anything and tuck up into the floor, etc., etc..

So: congratulations on a job beautifully done!

John Parsons