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.”