Generation IV Internal Engine - over 400cfm possible on l92 heads?
12-10-2011, 10:20 AM
Hey guys, just moved down here from ia a couple months ago and was wondering about this? ive herd of cutting the intake valve down 2.120 and makes a big difference on the flow bench when testing on a 4in borestand, but does anybody have track times or dyno numbers? this is for a 4.-4.030 bore deal, i never got a chance to try it before i moved.does anybody have any (helpful) info on this? thanks again,Brian
12-10-2011, 10:39 AM
The intake side is not the problem... It is the exhaust side.
12-10-2011, 11:08 AM
Look up Pwebbz on here. He had a crazy port job done on his heads and they were still flowing at .750+ lift. I can't remember if he reached 400cfm or not
His motor made 700+ hp though
12-10-2011, 11:14 AM
yeah, i understand this head is a good choice for 4.065 bore and bigger, just wondering if anybody has tried cutting the valve down to unshroud it for the 4in bore? 6.0? just seeing if anybody has tried it or is it a waste of time,lol. ive herd 400cfm, but havent seen it or herd if it translates into power.
12-10-2011, 11:19 AM
4in bore? what size motor?
12-11-2011, 11:04 AM
there are people that cut down the intake valves,but as always depends on the application.
you could probably reach 400cfm with these heads,but port velocity would drop like a rock.quality of flow is a lot more important than quanity.flow #s alone don't tell you how good a particular head will perform.
12-11-2011, 10:25 PM
nobody? i know there are some good head porters down here in the houston area, just wondering if its worth doing. 400cfm no big deal if it dont show up on the track.Head porters and engine builders please chime in guys, thanks again guys,Brian
I believe Greg Good has hit close to 410cfm on an all out LS3 head. It probably wouldn't be a good combination for a 4.00-4.030 bore setup though. People do commonly run cut down valves when running these heads on smaller bore motors though.
12-11-2011, 11:15 PM
I have seen flow sheets at 392cfm with the stock 2.165 valve, 269cfm on the stock exhaust valve.
12-11-2011, 11:17 PM
Thanks you sir, anyone else with info?
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