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Venom Performance works with KPMI/ Kibblewhite Precision Macining to create custom valvetrain componets for high output endurance racing applications.
KPMI spring kits use titanium retainers to lessen valve inertia, and also use dual springs to lessen the effects of vibration harmonics. Harmonic Vibration is a horrible thing to valvetrain control. The springs already have a tough job keeping valve motion true to camshaft motion at high rpm. Add a vibration to the spring and it becomes much less effective at its main job of stable valve motion. Two springs of different thickness and shape will not vibrate at the same frequencies. Also, if one spring is in a vibration state, the spring that isn't will dampen and absorb the unwanted harmonic. Dual Rate valve springs with titanium retainers are the absolute ultimate for high performance valvetrain reliability.
Valves are made from either high grade stainless steel or titanium. original equipment intake valves are trypically made of a lesser grade of steel than are the exhaust valves. Original equipment exhaust valves need to be made of better material because of the heat load they encounter. all of Venom's custom SS valves are made of the same high grade steel, in most cases this is a longer wearing upgrade over oem steel intake valves.
Titanim valves are lighter than SS valves and that light weight means lighter spring pressures can be used without fear that the valves will float or bounce at higher rpm. The faces of titanim valves do not need to be dished out to save weight, and this flat\non dished face will add a bit of compression by reducing combustion chamber volumes.
The material of a valve does not make a difference on power output (not counting the slight compression bump from flat faced titanium valves), but the profile of a valve does! The biggest resrtiction to port airflow in a 4-stroke engine is that fact that the valve is a huge obstruction placed right smack in the middle of the flow path! The shape of a valve as well as the shape of the seat, can be optimized so that the profiles aid in getting airflow past the valve. This becomes especially beneficial the closer the valve is to the valve seat, which happens twice during the valves open cycle. Correct valve and seat shaping aids in airflow in the same manner that porting does. More flow equals greater power output.
All Venom Valves have custom profiles using "back cuts" behind the 45 degree sealing face. These custom cuts help form a venturi, and when coupled with proper seat angles, they increase airflow at low to medium valve lifts.
If you need to replace valves, you might as well take advantage of Venom's custom valves that act like porting!