42 ENGINEBUILDERmag.com | AUGUST 2020
A pedestal-style rocker is another
option available, which is often seen
on LS engines. Like everything else,
rockers can vary greatly depending on
application.“Within each level of our
rockers, you can choose to lighten
them or not to lighten them,”
McDonald says. “If it’s a supercharged
application, you don’t want tolighten them, you want them heavy
because there’s a lot of a de ection
and cylinder pressure. ere’s also
an option between a cup and a ball
adjuster, again, depending on lift and
application. e ball, the rocker and
the cup on the pushrod help with
angle and to keep the rocker stable.”
If your looking for stock
replacement options for your rocker
arms stamped rockers are an option
and are many times available in
di erent ratios and slot lengths so you
can customize your valve lift and have
the clearance needed for higher lift
applications.
“ e next step up,” says Gathman,
“is a stamped, roller-tip rocker, which
reduces the rolling friction at the valve
stem. ese give a slight advantage in
horsepower that would otherwise be
consumed in the valvetrain, and they
extend the wear life of the valve stems.
“ e best choice for spring
pressures up to 800 lbs. and more are
stainless steel roller rockers. ese are
fully machined from billet and have
roller bearings for pivots and at the
valve tip.”Pushrods
Pushrods are another piece of the
valvetrain puzzle. Pushrod engines
tend to get some ack for being
outdated, but there are plenty of
advantages to them. Pushrod engines
tend to produce good low-end torque
due to better air velocity at low rpm.
Increasing the velocity of the intake
air means the air and fuel mix better,
providing better combustion and
torque.
Another advantage is the
simplicity of the engine design itself.
A pushrod engine is a much simpler
solution than a dual overhead cam
engine. at’s not to say one is
necessarily better than the other or
more or less reliable, though.
A pushrod is required to transferTHE VALVETRAIN
40-43 eb.aug20 Valvetrain.indd 42 8/7/20 8:32 AM
Naresh Jariwala