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lucittm lucittm is offline
Manassas, VA
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Join Date: Apr 2007
Posts: 1,211
I don't think you would need to change your cams for this kind of upgrade.

Everyone sends their heads out for twin-plugging. Yes, the the shipping cost is not trivial, but this is specialized work. My brother was born in Ontario, so I know your area a little. I would recommend someone on the east coast such as Xtreme Cylinder Heads in FL. Their advertised price is $350.00.
Also, JB Racing is in FL.

I am not familiar with a Promotive stage 2 kit. My opinion is that the .05mm shim at the base of the cylinder will be just enough to upset the 140K miles of wear that your pistons and cylinders have accumulated. Maybe not. That shim will have very little effect on your CR.
The 1mm head gasket ring will reduce the CR. I'm not sure it will drop it to 8.8 and I'm not sure 8.8 is low enough. Even the newer 3.6 turbos only run 8.5 and they have forged pistons.
But you are correct, the impact to the cam chain deflection will be minor. However, the cam chain cases will no longer be in alignment with the cams/cam towers. This will require shimming the chain cases or shaving the cam towers.

ARP studs and a new exhaust system are worthwhile upgrades.

1991 964 Polar Silver Metallic Turbo Coupe

Last edited by lucittm; 01-21-2009 at 05:12 AM..
Old 01-21-2009, 05:08 AM
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