exhaust system pcv?

Bought the jegs kit - two breathers and two weld-in one way valves [ ATTACH ] 1714774828 [ / ATTACH ] the instructions say to install towards the end of the headers? But I have 3 " collectors into 2 1/2 pipes into 2 1/2 cherry bombs into 2 1/2 pipes out the side. I'm wondering if it would be better to put it in the two and a half inch pipe instead of the 3 inch collector maybe before or after the cherry bombs to avoid any back pressure?View attachment 20141210_215325.jpg

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I know there's a lot of guys that use the system I've seen it at the drag strip I just am not sure exactly where to put the one way valve?