89ROC-Z

iTrader: (11)

need exhaust for my motor.....and the only company that makes headers that fits is Stainless Works, and they only offer 1.75 or 2" primaries. Rev limit at 7k, 150 shot of n2o, stock ls3 heads/intake, aggressive cam.

What do you think? the 2" headers will be about ~$250 more than the 1.75

99SSJarhead

iTrader: (2)

Do you have an estimate of what your current HP is? 1.7/8 will take you pretty far before they start acting as a restriction on air flow.

Darkman

iTrader: (2)

All else equal, 2 inch pipes flow 41% more than 1 3/4 inch pipes and 18% more than 1 7/8 inch pipes.

LS1-450

iTrader: (33)

Wow, that's a good question. I'd try asking in the dyno section. Do know that a lot of guys w/ ls3's swear by 1-7/8" primaries. IDK, what the effect of 2" would have. Exhaust flow get kinda "fuzzy" to me when the gurus start talking about "best pressure/scavaging/flow" relationships.

Might also try in the "advanced discussion" section. There are still a few guys, who hang out in there, that know there **** & have been around forever.

Good-luck w/ this & let us know what you end up doing & HP/TQ results if possible.

Hard Core Z28

Unless it is an all our drag car that doesn't see the street the 1 3/4 is all you will ever need. bigger is not always better.

01ssreda4

iTrader: (96)

Biggest you can afford. Go 2 inch.

nmass399

1 3/4 will be the best. 2 inch primaries are way too big for a 370 street motor and will lose a **** ton of low end. Plus there could be fitment issues because of the extra primary size. Bigger is not always better.

89ROC-Z

iTrader: (11)

How much low end would it lose?? I've seen people gain 20+ wrhp going from 1.75 to 1.875....

87silverbullet

iTrader: (11)

I asked the same question a long time ago and there was a guy who responded to my thread and he was using 2 inch on a 370 and he reported no loss and the car felt good. Here you go post 10.

https://ls1tech.com/forums/generatio...body-done.html

89ROC-Z

iTrader: (11)

damnit idk what to do now....i've only seen people gain hp and torque going to 1.875 vs 1.75...the 2" ones are a 1/4" bigger than the 1.75 and that seems like a big difference to me

Darkman

iTrader: (2)

What size collectors come on the 1.75 inch and the 2.00 inch primaries?

LS1-450

iTrader: (33)

Yah, it is. That's why I wanted to hear about your results if you choose to use them.

Jim85IROC

iTrader: (6)

I'm facing the same issue right now myself. I emailed Stainless works to find out if they could build me some 1 7/8" longtubes, but they haven't responded yet.

89ROC-Z

iTrader: (11)

^^Jim, i did the same thing and they said they will not make any other headers for individual people, they have a contract with Bruce over at Hawks.

I think i'm going to get the 2"....Bruce is giving me a deal on them and they will be the last headers i'll ever buy for the camaro, should leave me plenty of room to grow lol

Jim85IROC

iTrader: (6)

I even worded it to be clear that I am just as happy to buy the headers through Hawks if necessary, but so far still no response. It looks like I need to decide between 1 3/4 or 2".

89ROC-Z

iTrader: (11)

^^ Go 2" with a 402 IMO, that's kinda why i'm getting the 2" right away...got another 6.0 on the stand waiting for a 408 rotating assembly.

BlackScreaminMachine

iTrader: (17)

Seems to me that most people's setups cannot take advantage of the larger primaries. I have seen my share of examples and most times there was not a benefit. It did not hurt it but nothing overwhelming. But again thats my opinion.

But as long as you do not mind dealing with fitment, you should be fine.