ive been looking around at some heads and the flow numbers for aftermarket heads seem low? i been looking at the ls1 afr 225s but their flow is like 320 @.600 is it possible to get ls1 heads super ported to get like 400 cfm? is there just not enough meat to cut away to get that high? or is 320 like insanely good? im not real sure. most places dont even give flow numbers, its hard to compare

 

320s are about as good as you can get.

400cfm heads...good luck

 

well what is the reason? like i said not enough meat to cut away?

 

Try; ET Performance C5 R heads ................ warning very pricey

 

Go big block.

 

Check out this page to see a chart of flow #'s. Click on the tab for "All Heads" along the bottom, otherwise it defaults to "LS6 heads" only.

The highest intake flow I see on there is 346, but that's for a set of 6.0L heads. 307 is the highest I see for any of the LS1 heads. LS6's are as high as 335. IMO, I'd say that a set of LS1 heads flowing ~320 cfm @ .600" is probably about as good as you're gonna get? In terms of exhaust flows, it seems LS1 heads don't trail LS6 heads quite as badly.