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Surface milling of cylinder heads to resort the gasket surface is often done with little regard for restoring the proper angular position of the head's chambers and ports

We feel this step is one of the fundamentals in any blueprinted engine. If the gasket surface is improperly cut, or if the original surface is used as a reference plane, there no guarantee that the chambers or ports are in the proper relationship with the cylinders or manifolds.

In the worst cases, the chambers may actually have more volume at one end of a head than at the other due to an error in machining. At Valley Head Service, we take the additional steps to assure you of a finished casting that fits, and is parallel to the crankshaft axis.

Surface And Angle Milling

Angle milling has become a standard practice on racing engines over the last twenty years, offering improvements in port entry and exit angles, and the angular relationship between the block deck and valve faces.

The tough parts of this job, when properly done, are accurately re-cutting pushrod bores, re-drilling and re-spot facing head bolt holes, correcting the intake manifold surface angle, and the many other details involved in restoring the head to "bolt-on" shape.

We've been angle milling heads for all of those twenty; we avoid the common errors, such as weakening the gasket face to the degree that i shifts and causes gasket failure. WE DO IT RIGHT!!

Professional Series Porting	Competition Series Porting	Street Master Series Porting	Mileage Stretcher Series Porting
Designed for installations with Isolated Runner manifolds, or intakes with very large plenum volumes and dual carburetion or fuel injection. Roller cams are recommended. Most Professional packages utilize new casting, lightweight valves, titanium retainers, bronze guides, hardened keepers and Perfect Circle seals. Because of the many variable and specialized engineering involved, please discuss your engine requirements with us.	Designed for road racing or circle track installations with single carburetors and single or dual plan manifolds. Competition porting extends from each gasket surface to the valve seat, with the ports enlarged to the maximum possible size for the engine application. Valves and seats are shaped for the application, and the seats are cut within 0.0001" TIR. Competition porting provides exceptional performance with electronic fuel injection.	Designed for street, mild competition, and off road installations where midrange torque is a prime factor in overall performance. Intake ports are cut to maximum gasket dimensions, and grinding extends approximately one and a half inches into the intake port volume. Valve pockets are shaped for optimum control of the intake charge or exhaust gases around their respective valves. Exhaust ports are fully ground for excellent scavenging. Valve sprints heights are held within 0.005" of the cam maker's specifications. Street Master heads provide excellent throttle response and performance with single carburetor aftermarket manifolds and properly sized headers.	Designed for excellent response and fuel utilization in the lower rpm ranges. Mileage Stretcher heads offer improved performance through re-contoured valve pocket areas. Port volumes are left alone to maintain charge velocity, which contributes to the good throttle response so often necessary in RV applications. These heads are particularly good for RV, tow vehicle and truck applications with stock or milk gearing, good carburetion and an efficient intake manifold.