Milling LS6 heads with EPS 230/238 0.600"/0.604" 112+2 cam?
03-28-2011, 12:11 PM
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Milling LS6 heads with EPS 230/238 0.600"/0.604" 112+2 cam? Hey guys, just wanted to post up that I'm really excited to run a new head/cam setup in my 1993 Mazda RX7 LS1/T56. After a lot of research and debate (+talking to Geoff), I opted for the cam mentioned in the title over my other option which was the EPS 226/234 113LSA. I am matching this cam to a set of PRC LS6 stage 1.0 heads (stock valve sizes) with dual springs... I think this is going to be a pretty slick setup for my car and would love to see 10's N/A (previous best was 11.6 @ 119 w/TR224 only). I am also considering spraying a 100-150 shot of Nitrous down the line for low 10's. 
Here's where my question comes in. I would like to bump up my compression to around ~11.0 to help make a little more power down low. When I talked to TSP (thanks for the help), they estimated I could clear with the heads milled down to 61cc without flycutting, I assume this would be around 0.020" off the head. I have literally done countless hours of research to try to verify this for my own peace of mind. Since it's a new cam without a whole lot of info I have been trying to find what people have found to work with the TSP 230/236, 231/237, 233/239, F13, etc -- all on 112LSA. It seems to me that it should clear with stock MLS gaskets... the closest comparison I found was a member who is running the 230/236 +112 LSA with the same LS6 heads milled 0.015 AND is using 0.040" cometic gaskets. I would love to know if anyone else can verify this clearing comfortably without flycutting.
The other option I have is to get the heads UNMILLED and run a 0.040" cometic gasket (equivalent of milling heads 0.010-0.015). The benefits of this would be a tighter quench and better potential resale value down the line. The disadvantages would be the set of gaskets costing 4X, probably getting less compression than I want, and the reliability issues that these gaskets have given some members.
I know everyone's going to say you gotta check PTV, and I will. But that doesn't escape the fact that I would like a ballpark estimate first. So, if you were me; what would you do?
Here's where my question comes in. I would like to bump up my compression to around ~11.0 to help make a little more power down low. When I talked to TSP (thanks for the help), they estimated I could clear with the heads milled down to 61cc without flycutting, I assume this would be around 0.020" off the head. I have literally done countless hours of research to try to verify this for my own peace of mind. Since it's a new cam without a whole lot of info I have been trying to find what people have found to work with the TSP 230/236, 231/237, 233/239, F13, etc -- all on 112LSA. It seems to me that it should clear with stock MLS gaskets... the closest comparison I found was a member who is running the 230/236 +112 LSA with the same LS6 heads milled 0.015 AND is using 0.040" cometic gaskets. I would love to know if anyone else can verify this clearing comfortably without flycutting.
The other option I have is to get the heads UNMILLED and run a 0.040" cometic gasket (equivalent of milling heads 0.010-0.015). The benefits of this would be a tighter quench and better potential resale value down the line. The disadvantages would be the set of gaskets costing 4X, probably getting less compression than I want, and the reliability issues that these gaskets have given some members.
I know everyone's going to say you gotta check PTV, and I will. But that doesn't escape the fact that I would like a ballpark estimate first. So, if you were me; what would you do?
Last edited by mattster03; 03-28-2011 at 12:20 PM.
03-28-2011, 07:09 PM
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Keep the heads with stock cc and get a 0.040 cometic gasket you'll get almost 10:8 cr
Cuz whenever you want to go for a bigger cam you wouldn't regret milling .
Cuz whenever you want to go for a bigger cam you wouldn't regret milling .
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03-29-2011, 12:08 AM
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Hoping to make a little more powerup top with the slightly higher duration. I'm ok with sacrificing a little down low since my car weighs in at 2750#... doesn't take a whole lot to get that weight moving 
. I am debating between the PRC duals and 918s... probably going with the duals for my future nitrous option and to resist valve float at the high rpms
. I am debating between the PRC duals and 918s... probably going with the duals for my future nitrous option and to resist valve float at the high rpms
03-29-2011, 03:21 PM
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I'm actually leaning toward a set of Livernois Stg 2 LS6 heads now. I think that the 220cc Intake runners will be better suited toward my cam specs with very close to the same flow as PRC stage 1.0 LS6 heads but have 235cc chambers. Livernois will also mill my heads to 62cc / 0.015". Anyone able to talk me out of the Livernois over the PRC's?
Last edited by mattster03; 03-29-2011 at 03:47 PM.
03-29-2011, 03:46 PM
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i don't think that would be a problem for me... I figure anything bigger and I'd be getting forged pistons that I could order with reliefs in them anyway!
