Discussion
Well of course Ill spout my thoughts 
If you do lots of reading about the place you will come to the conclusion that 1.7/8 primary long tubes are best.
Check this out http://www.ls1tech.com/forums/showthread.php?t=981...
Some say 1.3/4 are fine, others as above 1.7/8 if you are going for big power, then 1.7/8 are probably your best bet.
So if you are only after something in the 400-500 odd range then 1.3/4 should be more than enough IMO. For good gain stock with bolt on's 1.5/8 are even good.
Anything over 550fwhp is suggested to run dual 3" exhaust (cat back). This is based on 1 inch square of pipe flowing 112cfm and 2.2 cfm of flow required for zero loss per bhp. Also make sure your cats flow properly. Maybe with 3" in and 3" out metalic cats.

So you can get your calculator out on that one and read up more from here http://www.popularhotrodding.com/enginemasters/art...
"Exhaust Science Demystified, The fact is most cars are leaving horsepower on the table. We show you how to get it back."


If you do lots of reading about the place you will come to the conclusion that 1.7/8 primary long tubes are best.
Check this out http://www.ls1tech.com/forums/showthread.php?t=981...
Some say 1.3/4 are fine, others as above 1.7/8 if you are going for big power, then 1.7/8 are probably your best bet.
So if you are only after something in the 400-500 odd range then 1.3/4 should be more than enough IMO. For good gain stock with bolt on's 1.5/8 are even good.
Anything over 550fwhp is suggested to run dual 3" exhaust (cat back). This is based on 1 inch square of pipe flowing 112cfm and 2.2 cfm of flow required for zero loss per bhp. Also make sure your cats flow properly. Maybe with 3" in and 3" out metalic cats.

So you can get your calculator out on that one and read up more from here http://www.popularhotrodding.com/enginemasters/art...
"Exhaust Science Demystified, The fact is most cars are leaving horsepower on the table. We show you how to get it back."

MyM8V8 said:
Short tube headers, as these are, will be slightly better than the stock cast iron ones, but the most effective , for our application, would be long tubes. Note the short collector too, a longer one is better.
there were long tube header form the same seller for simular money. Was thinking if i went for the full milltek system if these OBX header were the same dimension as the originals i could fit them with the Milltek. Obviously long tube headers wont fit with the Milltek
longtubes will fit the Miltek but you'll need the cat pipes modified to fit which any decent custom exhaust place should be able to do. Roger thought the Wortec headers may fit straight on with their cat pipes but according to Mark at Rapid although they look like they terminate at the same place as a stock exhaust they are spaced slightly differently so you cant get them to line up - think he got caught out with this before with a customer's car. I do know LSV used to stock headers suitable for the Miltek but whether they still have them or are still operating a garage I couldnt say for sure.
rickf_uk said:
Hmmm... I've looked at these US headers before but general opinion on the site was that steering rack on our RHD cars was going to obstuct thier fitting. They're a good price but only if they fit.
So there is no confusion US headers will not fit.As said the headers loop around the steering column on the appropriate side.
A few good suppliers in Oz if the 1-3/4 wortec headers aren't what you desire.
MadMaxHSV said:
So there is no confusion US headers will not fit.
As said the headers loop around the steering column on the appropriate side.
A few good suppliers in Oz if the 1-3/4 wortec headers aren't what you desire.
Speaking of which, did you confirm yours as stainless under the paint in the end mate?As said the headers loop around the steering column on the appropriate side.
A few good suppliers in Oz if the 1-3/4 wortec headers aren't what you desire.
Yes, spoke to Darren again.
The headers obviously weren't under question but the rest of the system including the cats is all stainless, they just liked the look of it painted black. I suppose it stops the desire to keep it clean all the time
Did you get your headers coated in the end?
The headers obviously weren't under question but the rest of the system including the cats is all stainless, they just liked the look of it painted black. I suppose it stops the desire to keep it clean all the time

Did you get your headers coated in the end?
http://cgi.ebay.com.au/LS1-LS2-GEN-3-
what about these bad boys
dont know how much to get delivered though!
what about these bad boys
dont know how much to get delivered though!MadMaxHSV said:
ringram said:
Yeah same as yours.. painted black.
Off to Rogers tomorrow.
Were your headers painted black?Off to Rogers tomorrow.
Got mine HPC Ceramic coated inside and out. Nice silver/chrome finish.
Some rough handling has resulted in the stainless being visible underneath. Its all at Roger's now awaiting transformation.Im sure the paint will come off the headers at least making them age to silver, which should be good.
I could just about fit my hand up the exhaust ports on the LS7 heads, nice.
racebreed1 said:
http://cgi.ebay.com.au/LS1-LS2-GEN-3-HSV-HEADERS-E...
what about these bad boys
dont know how much to get delivered though!
They look ok, but you want to see how the merge collector works. It should all come to a point in the middle. Some just end in rough cut pipe, apparently makes a good bit off difference, maybe ask for a pick of inside the collector.what about these bad boys
dont know how much to get delivered though!ringram said:
racebreed1 said:
http://cgi.ebay.com.au/LS1-LS2-GEN-3-HSV-HEADERS-E...
what about these bad boys
dont know how much to get delivered though!
They look ok, but you want to see how the merge collector works. It should all come to a point in the middle. Some just end in rough cut pipe, apparently makes a good bit off difference, maybe ask for a pick of inside the collector.what about these bad boys
dont know how much to get delivered though!Gassing Station | HSV & Monaro | Top of Page | What's New | My Stuff


