Update.....Geoff and I had been talking during the Dyno Day this past Sat. and he wanted me to look at the stock headers.........amazingly, and quite surprising to us both, the stock headers actually had LARGER inlet openings vs. the header Geoff had originally wanted to use.
Now if you take a real close look at the pic, you will also notice the stockers actually open up a bit after the second collection point allowing for better flow than the other. Outlet openings are about identical.
So Geoff is going to use the stock headers instead of the other design. I never would have guessed that GM had got this bit correct......
To all of you that have used the stock headers, way to go!
2009 G8 GXP, SRM, M6, Onyx, Roof. (#1818 of 1829) a.k.a Gianna
Show: Tint, VG Sharkfin, 3M clear bra, 6000k HIDs, 20" TSW Interlagos.
Go: BMR, GForce, MGW, Monster Clutch, 3" SOLO, Dynotech, Squash DW255s, Tein, NLP Twin Turbo!
Stock: 363 whp/367 tq SAE (Dyno Jet) 13.149 @ 108.21 mph
Mods (old): 399 /399 SAE (Dyno Jet) 12.711 @ 108.66 1.548 60' w/MT ET Streets
Mods (new): 602/614 SAE 10 psi, 6* (Dyno Jet) 11.33 @ 125.26