CNC Machined Cylinder Heads

We've taken something great and made it even better! Now our heads are available fully CNC Machined on both the intake and exhaust ports.

These are fully machined by Jeff Kobylski at Modern Cylinder Head in Michigan.

Heads are 100% CNC ported on their Fadal 5 axis CNC machine.

Modern Cylinder Head sizes and checks the bronze guides for correct clearance, then performs their precision multi angle valve job on their Serdi equipment. All valves are then lapped to verify a good seal.

Heads are then surfaced on Modern's Peterson RP 900MVA Surfacer.

Valve spring installed heights are checked and shimmed if necessary.

Finally all parts are cleaned and assembled.

All work is done 100% in the USA, at Modern Cylinder Head's shop in Michigan.

Part No: 200-1081 - Stealth Aluminum Cylinder Heads - CNC PORTED - ASSEMBLED PAIR - Price: $1995/pair

 

Flow Chart: CNC Stealth Cylinder Heads
Flowed at 28" on a 4.380" bore with a Superflow 600 bench.
Exhaust flowed with 2" tube.

Valve Lift: Intake CFM: Exhaust CFM:
.100" 75.0 72.9
.200" 156.7 124.8
.300" 219.8 166.4
.400" 266.2 198.1
.500" 298.8 219.3
.550" 306.2 228.6
.600" 314.9 233.3
.650" 320.7 238.2
.700" 320.7 243.8
.750" 321.6 248.2

All specs on the head castings and valvetrain hardware can be found on our CYLINDER HEADS PAGE.

Over a pound of aluminum is removed from the ports during CNC machining, taking over 43cc's out of the port. This enlarges the intake ports from the stock 212cc's out to 255cc's!  Because the automated machine which does the porting is fully computer controlled, it can produce results which are identical and repeatable down to accuracies measuring in the thousandths of an inch. This means all ports will be exactly the same shape and volume, ensuring the flow numbers are consistent and accurate for EVERY port on EVERY head.

Another view from the port window side of the intake port shows what a straight shot the intake port has. An intake port that flows over 320 CFM will put the average stroker motor well into the high 600 to low 700 horsepower range.

The exhaust ports are just as nice as the intakes. The seats are blended perfectly into the throat of the port.

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