Last time I talked with Tim Banning, my Junk Hemi heads that flow 450-460 are now where near the 500cfm his street Hemi stuff flows...And he said on the race heads, they are damn near 600cfm...He said every Hemi head that leaves his shop flows +500cfm...

But if you don't get the oil control right, it won't matter.

'70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft)
https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car)
https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car)
https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9)

'66 Barracuda AWB Stretched nose Blown 440 Car in build stage

'71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph
https://www.youtube.com/watch?v=Znuo3jMUXTk