Valve to piston clearance question....
Valve to piston clearance question.... I am going to purchase some new AFR's 205 for my stock shortblock LS6 (01' z06). Here is my current set-up which is not making the kind of power I am looking for. 405RWHP and 360 RWTQ.
LS1 Casting 853
212cc Intake port volume
67cc Combustion Chamber
2.08 / 1.60 valves
Cam spec
595/595
237/242
112 LSA
Here is my question.
Using my same cam and with the AFR heads how much can I mill them without cutting into the pistons. Should I go to a smaller cam?? AFR recommends 226/230 but I am getting a lot of conflicting info. The AFR's have 65cc chamber out of the box. I am looking at getting less than 11:1 comp ratio so I can run pump gas on my second car. Still want driveablity, which is questionable right now. Looking to put down 440RWHP and 420RWTQ. Any EXPERT advise would be greatly appreciated. Thanks!!!
LS1 Casting 853
212cc Intake port volume
67cc Combustion Chamber
2.08 / 1.60 valves
Cam spec
595/595
237/242
112 LSA
Here is my question.
Using my same cam and with the AFR heads how much can I mill them without cutting into the pistons. Should I go to a smaller cam?? AFR recommends 226/230 but I am getting a lot of conflicting info. The AFR's have 65cc chamber out of the box. I am looking at getting less than 11:1 comp ratio so I can run pump gas on my second car. Still want driveablity, which is questionable right now. Looking to put down 440RWHP and 420RWTQ. Any EXPERT advise would be greatly appreciated. Thanks!!!
The valve drop (the distance from the deck of the head to the valve edge) on a stock head is .150", the AFR head at 66cc is .120", the valve drop on a TFS 215 at 64cc is .155" In back to back dyno testing the TFS head made more power. So my advice is to go with the TFS head, you will get more compression, more power and .035" more piston to valve clearance. All pros and no cons, whats not to love about that? 
I think your 67cc chambers are killing you. You can safely bump up the compression and still run pump gas, especially with a cam that big bleeding off your DCR. Try milling the heads you already have.
