Join Date: Feb 2009
Location: Timmins, ontario
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I looked HIGH and LOW for GM flow rates. i had A LOT of trouble finding anything other than stan weiss's data which...well.. was not a lot of unported info for GM big blocks. Simply put. theres a reason GM guys go aftermarket. They have to.
courtesy of stan weiss cyl head flow data as written
Chevy Factory iron.
L29 vortech heads stock valve - 242/142 @ 700.
Oval Port 049 heads stock valve - 268/177 @ 700
Ford factory iron
iron 429 heads stock valve -272/177 @ 700
there was some GM Rect port on there that outflowed ford on the exhaust. did not list pipe or no pipe...and also !!!!!!118 CC heads!!!!also of note it was damn near impossible to find as cast flow numbers of the factory GM iron stuff. when you went to the ported stuff. scotty J's D0VE's on there made the GM iron stuff look pretty sad.
I know scotty has some E7 or F3 stuff to compare to the Vortech heads, i'm sure they make the vortechs look sad. there were some of scotty's F3 ported on there but i left them off to keep the comparo as cast.
Lots of ford guys info from Members here, Scotty J, Charlie Evans, Dfree383 (guessing its the same guy) lol
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