RPM WS6

iTrader: (3)

My '00 WS6 with an MTI B1 (221°) made 360 at the wheels with mid-lenghts, 2.5" Y-pipe, 3" catback, and unlocked 3500 stall. That was with an LS1 intake. With an LS6 intake, LTs, and true duals, it would've likely been about 375-ish.

Stock manifolds and cats will really hold back any decent cam. I would not expect to see any better than 33x rwhp with a fully stock exhaust (from the Y-pipe forward) with the mods the OP has listed.

To the OP, in addition to trying a stock, clean MAF, don't forget to look at your LTFTs and KR. You may be dealing with several small issues that are adding up to your total missing HP.

98ZEMT

iTrader: (5)

Thank you all for the advice. I am going to try to have a local place do a real dyno tune. I think most of my problems will go away. I hope at least. I just know it can't be anything mechanical. So I guess I'll go this route. Thanks again.

98ZEMT

iTrader: (5)

Well great. Now the car starting cutting off when placed in drive. This sucks. I will never never never never ever get another mail order tune.

98ZEMT

iTrader: (5)

I had the car retuned today and it only pulled 280 on a mustang dyno. After he got done with it it pulled 330! Much better I'd say.

RPM WS6

iTrader: (3)

Very good.

330 is about the number I expected all along, once the issues were sorted out. Now, add some LTs and ORY and you'll pick up another 30-40 horsepower.

98ZEMT

iTrader: (5)

Thank you. I am perfectly happy now. I just knew something was wrong with 311 or 280 or however much horsepower. I knew that wasn't right. My tuner also said he couldn't pick up on the ignition wires either. Don't know exactly why. They are cheapy ebay wires. Thought they would be ok. But I guess not. He's got some MSD wires on the way for me.