With that 2800 and some LT's you should be 12.9's at least no problem (that's what I hit with those mods)... given some more time I may have cracked a 12.8 as well, but I through in the cam and never looked back

 

WTF? Are you serious? That is crazy. Something had to be wrong with you car to gain 8 horses from LT's.

 

I was under the impression that the horsepower gain 10-15 or 15-25 was relitive to a stock car...

because if it releaves preasure it seems to me the more powerful the car, the more it would benifit the car. i.e. the 275 stock horsies under the hood, shorties gives u 10 hp... i figure if uve got about 500 horsies u'll get almost 19 hp... but i wouldnt think it was a fixed rate...

just a question and my 2 cents

 

8rwhp...ouch...something is up there. Did you notice any SOTP difference after installing the FLPs? I ask this because I just put Jet-Hot LTs and Hooker y-pipe on my car (ditched ye ole factory manifolds) and I know for sure I gained a lot more than 8rwhp - even running through the stock crappy TA cat-back. The car pulls much harder across the entire RPM range, especially in the top. I'd guess 15rwhp in my case and probably more like 25-30rwhp after I put on the Hooker cat-back in January. The SOTP meter doesn't lie!

EDIT: As a note, when I added a 3" cutout to the original factory exhaust I gained 14rwhp, measured on the same dyno with both runs back-to-back.

 

They are very nice headers for the price. But i would have to disagree about them being the best Mids for hp gains. They are only 1 5/8 diameter as apposed to as&m and slp's 1 3/4. I think the as&ms are the best mids, then the slps, then probably the macs. But for the money macs are very nice headers.

 

I'm biased though. Got them on my black car.

With my ASM headers Random Tech Cat and Cat back, I gained a SOLID .5 and 5 mph in the 1/4. Given that the stated number is approx 10 HP for every .1/1 mph in the 1/4 for our cars, then I'm looking at 50ish gain. Not too shabby.

 

I have got the SLP's and like them alot. For the actual HP#'s from them I can't really since I did the dyno things before I put them on. The good thing is that I kind of have baseline now, for what a stock LT1 will do with a P600B only. But back to what I was saying the SLP's that I have have been great and the car has a unscientific SOTP difference.

 

ASM are awesome headers, but pricey. If you ever see a camaro or trans am with MAC's installed you will run out and buy them the next day. I just saw them on my buddies Z about 2 days ago and will be buying them when tax returns come in. You can SEE ALL 8 PLUGS! He said changing plugs takes like 20 minutes. I dont know about ASM, but you cant do that with SLP's.

 

I have the jet hots and i felt a huge SOTP differance. the butt dyno does not lie. I have a stock ride hight, but the clearance is great with the jet hots. i dont think it would come into play to much unless your car was really low. I would highly reccomend the jet hot LT's

 

You say "Mostly stock". Now start doing some real mods and see how much you will love your FLP long tubes then.

 

You say bolt on headers? What are other options?

 

Sounds like your knock sensor is overreacting. Either buy an LT4 knock module or find someone with LT1 edit to deaden your sensor.