Some flow rates for you guy's from extrusion flow honing standard manifold ,hks cast iron manifold and hks cast iron flow honed
standard manifold .........hks cast ...............hks cast flow honed
1 159.7.........................170.7............................194.8
2 162.4.........................166.6............................203.4
3 160.7.........................178.7............................198.7
4 150.1.........................183.6............................200.3
5 149.9.........................182.2............................207.8
6 173.3.........................184.7............................202.8
Do not have any figger's for standard manifold flow honed but I do no he did a comparison between the standard manifold and a side mount s/s manifold like the one posted earlier in this thread and advised his customer to go with the standard manifold as a result last time I was there the s/s one was still there and he used it as an example of what not to buy ,I don't know if it was an ebay one or where it came from I'm just posting what he advised me as my son was after one of these same s/s manifolds and has opted instead to get his standard manifold flow honed instead when funds allow .As you can see flow honeing does make huge differances I also had the front cover and hot side of a gt3040r flowed honed at the same time to help with spoolup and it does work though I have no flow rates for these
Cheers Peter