Performance Valves and Seats :  Cylinder head re-configuration is useful to improve breathing and to alter engine performance characteristics.  This can be one of the most potent sources of increased power for any internal combustion engine.  Many factors come into play on custom machining of cylinder heads, with the primary utility of the vehicle to be the first consideration.  Heads can be re-worked with torque at low end, high rpm horsepower, or even fuel economy and engine efficiency as desired target results.  The following valve train components can help reach desired cylinder head efficiencies.
The Valve itself:
Performance valves can:
1.Flow more: Re-sized (larger or smaller), polished, swirl finished, lathe turned, & undercuting are all possible on replacement valves to allow target flow rates.
2.Last longer: made of different materials better able  to withstand the increased temperatures and corrosive exposure created by performance engines and exotic fuel blends.  Can also be chosen to withstand different valve to seat pressures. 
3.Rev higher: can be possible when lighter materials and alloys are used in forming the valve.
4.Alter valve train geometry: custom lengths and stem sizes possible for altered valve train necessities such as modified rocker arms or liter/follower configurations.
The Valve Seat:
Valve seats can:
1.Flow more: OEM Valve seats can be replaced or re-shaped to allow better flow. Different configurations and sizes of replacement seats are available that can allow modified flow.  Different inside and outside diameters are possible, as well as depths and tapers to better suit custom valve bowl and port designs.
2.Last longer: made of different materials and alloys, the replacement seats can be chosen to withstand increased temperatures and resist corrosive properties of exotic and traditional fuels.
The valve to seat contact pressures can also be allowed for when changing spring properties and camshaft profiles, which all affect the valve contacting the seat.
Some of our Diesel high performance valve offerings:

12 valve Cummins 5.9L: 
 (2.5)mm oversize Stainless  Steel intake and exhaust valves.  Intake valves are 1.870" and exhaust valves are 1.750"'​  
​​24 valve Cummins 5.9L: 
(1) mm oversize diameter Stainless  Steel valve suitable for intake or exhaust. 34 MM (1.340")
Cummins 6.7L​:
(2) MM oversize diameter Stainless  Steel valve suitable for intake or exhaust. 35 MM (1.380") 

Duramax 6.6L:
(1) MM oversize  Stainless Steel intake. 34 MM (1.340")
(2) MM oversize Stainless Steel exhaust.  33MM (1.300")

Ford 6.0L & 6.4L:

(1.2) MM oversize Stainless Steel intake valve. 35.2 MM (1.385")
(1.85) MM oversize diameter stainless steel exhaust valve.  29.85 MM (1.175")
We have special kits available for all valve offerings. Kits include valves and seats, and options include various spring options, titanium retainers, and Chrome Moly push rods.  Please call for special pricing and custom kit configuration.
We have our own design Cryogenically treated Chromoly push rods available for Cummins 3 and 6 bt designs, Ford 6.0, 6.4, and 7.3 engines, as well as the GM 6.6 diesel engines.
Mountain High Performance               303-420-6218                  5293 Ward Road #3               Arvada, CO 80002 
Tried and true!  MHP one piece stainless steel oversize valves for huge cylinder head flow possibilities without custom valve prices!!!   In stock now!!!  call 303-420-6218