TECH A GREATER CRATE
The Chevrolet Performance
SP crate is advertised
at hp (at , rpm)
and lb-ft (at ,
rpm). Well, as you can see,
those numbers were nearly
identical to what
we nailed down on
Westech’s Superflow
dyno. This was done with
the included GM single-
plane intake and a Holley
XP carb along with an
MSD distributor and a set
of Hooker dyno headers.2
We felt the cam that came in the
SP wasn’t big enough to really take
advantage of the supplied single-plane
high-rise GM intake. Fortunately, GM
makes it easy to swap intakes since the
Fast Burn heads are drilled for both
standard and Vortec-style intakes.3
We decided to try out an Edelbrock
RPM Air-Gap dual-plane intake. Given
the smallish cam specs (/-degree
duration, ./.-inch lift, and a
-degree LSA) we felt this would really
wake up the engine in the lower rpm
range where most street driving is done.4
And go figure, we were right. With the dual-
plane intake, the stroked small-block made
considerably more torque and a bit more
hp all the to , rpm. After , rpm the
single-plane makes more steam, but only by
a little bit. For a street car we would much
rather have this combination.5
“While the world is busy
fawning over LS and LT
engines, there’s nothing wrong
with good old small-block
power. Besides, it’s less cash
to get in your car and fired up.”