This head was designed for
one purpose, HORSEPOWER.
The advantage of 4 valves per
cylinder is this. A HUGE valve area increase. As a comparison, most high
performance cylinder heads for a 4" bore use a 2.0" intake valve and a 1.7"
exhaust valve. The curtain flow area with 2 intake valves of 1.72" diameter
each is equal to a single valve of 3.44" diameter. (curtain flow area is
defined as the perimeter of the valve multiplied by the height of the lift,
multiplied by 2 valves). And the curtain flow area of 2 exhaust valves of
1.476" diameter is equal to a single 2.953" diameter valve.
With the 4 valve heads we
generally use this huge valve area with the same size ports as used on a 2
valve head. In everyday terms we are OPENING the door faster, and keeping it
open longer. This fills the cylinder more fully on the intake cycle and
evacuates the cylinder more completely on the exhaust cycle. This reaches
the same high port velocity as a 2 valve head, but maintains that same port
velocity much longer. This is why there is no loss of low end torque, but
much more mid range and top end power.
We designed the heads for use
with all standard equipment such as manifolds, cams etc. for ease of
installation for our customers and the cost savings of not needing top buy
costly parts unnecessarily.
Head kits come with everything
needed to install. Pair heads complete, rocker boxes, rocker arms, and valve
covers.
The heads are available now
for:
-
EVO with 4.0" bore and larger
-
Twin Cam 95"cu. in. and
larger 3 7/8" bore to 4.250" bore
-
Twin Cam 4 3/8" bore and larger
(relocated bolt holes)
*Patent Pending |
