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nippy nippy is offline
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Join Date: Jun 2010
Posts: 1,559
The heads are back from Bill at Xtreme Cylinder Heads. These are factory SC heads from my motor.

From Mike Bruns regarding what has been done to the heads:

Larger ports with proper shape and larger valves along with a precision valve angle and seat angles to help flow in and out.Working together all this improves the ability to make power.
With CNC porting everything is exactly the same where before being done by hand was very time consuming and close but not perfect, even the valve job is done with CNC machines

You also have twin plug using 12mm threads to reduce the chamber volume increase (which effects compression ratio) look at the picture of the original plug hole vs the new hole, we also reduced the valve stem size from 9mm to 8mm to reduce weight and increase air flow, the injector notch was welded up before the port work too.

82 911 Wide body/Miami blue/Mike Bruns built 3.6
80 911SC Black/tan (sold)
87 930 Turbo 505 slant GP white/black (sold)
95 993 C2 GP white/tan (sold)
82 911SC Hot Rod lightweight Black/black (sold)

Last edited by nippy; 12-05-2018 at 06:37 AM..
Old 12-03-2018, 06:44 AM
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