Quote:
Originally Posted by Megahurtz
1 7/8 inch is the right size for NA LT1 stuff. 2 inch causes more low rpm torque loss making the car feel sluggish and you will gain almost nothing up top over the 1 7/8 on an LT1.
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Not to mention unmolested heads exhaust ports are still smaller than the OE manifold. Going from blowing out of a straw into a cup vs blowing out of a straw into a bowl still leaves you just blowing out of a straw. This is also why jet coating can be worth it if you can get it done for a good price, as keeping the exhaust gases hot through the collector helps keep air velocity up. As well as a bunch of engineering I can't readily regurgitate. But everyone is always "Bigger is better" and they'll hog their heads, buy a random cam, and strap 2" headers on and say look at my peak numbers baby! Nevermind everything under the curve.
@Vince, don't rely too heavily on forums and reviews. I should say, take it with a grain of salt. The vast majority of people leave a review or make a forum post when they have a bitch or a problem. Compared to the total population of the forum membership over the years, the number of posts about header fitment issues is probably less than .5% of the membership and I'm not even looking, just taking a wild guess. I made a post about the GM OEM shifter design being a WTF-Terrible design and the engineer should be castrated to prevent further dumb engineering. I never made a post about how easy it was to bleed my clutch slave cylinder thanks to Tick Performance's bleeder line. I'm just saying, knocking long tubes because a few people had frustrating fitment issues doesn't mean they're all not worth doing. You will naturally have more fitment issues with 2" headers because they occupy a little more space and bends have to be a little bit longer. Aside from getting my header flange trimmed by like 1/8" to assure it was perfectly flat, I have Zero fitment issues. Mine are $600 Kook's knock-offs essentially. $100 to the machine shop, $180 to the exhaust shop to mate the collectors to the OE midpipe, and I'm still in them less than a set of real Kooks. I like to do all my own work most of the time, but there are certain things letting a pro shop do is just worth the money to not suffer the headache. My headers are so easy to install and remove, I have to have my wife hold the driver side header when I feed it up so I can get out from under the car to bolt it up, otherwise it'll literally just fall out of the bottom of the car. Texas Speed and other Vendors are going to warn of fitment issues because they don't want to hear customers bitching about fitment issues. You'll get on the phone with them, mad as hell you just shucked ~$1500 +/- and they don't just bolt on and fit flawlessly. Then they'll point at their disclaimer and tell you to pound sand. Then customers come here and vent to forum. Then Joshinator or some other forum vet will post up, Suck it up and roll up your sleeves or take it to a shop. On occasion there is a more serious defect in a set of headers, which most big brands warranty these defects. Sometimes it's a battle, sometimes they treat you real well, I think a lot of it is customer approach, if you come at them like a tazmanian devil I think you get the bronze customer service treatment. I've had a great experience on the phone with Katech/GPI/Phastek/BTR (except their cam engineer... he really doesn't like that I'm boosting their NA cam lol) so when you buy parts just keep it in mind they are who you'll deal with if you have issues, too.