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Old 05-07-2013, 04:34 AM   #9
derrickmanx1
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Join Date: Nov 2012
Location: Rising Star, Tx
Posts: 249
Re: Headers.....holding motor back?

Quote:
Originally Posted by derrickmanx1 View Post
I'd jump up to 1 7/8" minimum. 2" if you can.
Since I said this I dynoed my 408 bbc normally aspirated and my headers were not availible yet and we used a set of 2 1/8" headers. My motor made 496 hp @ 5600 479 ft/lbs @4700. In saying that the headers were too big for my motor. I lost more torque than anything on the dyno. I am running a set of 2"x3" headers from hedman. I did that so I could run nitrous and feel a little better about it in the end. I believe the increase from 1 5/8" to 1 7/8" would be good for a few horsepower like 2-5% but if you are in the 500hp range now that is 10-25hp. The only time you really would see a benefit would be above 4-5000 rpm. We have about the same size cams in our engines mine made 1.21 hp per cu/inch. Your's should be slightly better than that since you are running a blower. 2" might be too big but 1 7/8" even 1 3/4" should be slightly better.
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NAME: TRAVIS TRUCK: BRUISER
71 C/10 SWB 3.5/5" drop 4.11 GEARS.
F.A.S.T. BBC 408 496hp/479ft/lb
JAKES 4L80E TCI TCU PTC 10.5" 2800 STALL
My build thread: http://67-72chevytrucks.com/vboard/s...30#post5779530
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