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Are you using step headers and a merge collector?



The headers are off-the-shelf TTI stepped headers - 1 5/8"-1 3/4", coated in and out. The collector is a standard style, non-removable and somewhat short that I ran with extensions.

* Perhaps the exhaust system overall helped torque because my minimum weight is 3,530 and I usually run 20-40 lbs over that? Heavier than most 340/360 Stockers.

* I don't know if the X-pipe without mufflers would help more. Doesn't Nascar use X-pipes? But I got the Dynomax Ultra-Flos because the are straight through and seemed to flow well based on published #'s. (I kinda like the quieter sound now!)

* I wish I had time to devote to specific testing. I'd have to fab new hangers if the mufflers were removed. But I ran the headers open for several years and tinkered with the jetting whenever time allowed. Then it ran a little better leaned out a few #'s after the exhaust system was put on. Maybe .05, but not more than .10.