According
to my sister, a veterinarian, all dogs are descended
from a common ancestor. Every member of canis familiaris,
also known as the domestic dog, can trace its roots to
grey wolves that walked the earth 14,000 years ago. This
means that Duke, the chocolate Labrador retriever who
rules the Reher household, belongs to a family that also
includes yappy miniature poodles, towering Great Danes,
and every mutt at the Humane Society.
I bring the diversity of dogs
to your attention because it is an example of extreme
specialization. Through selective breeding, humans have
created an astounding variety of breeds with wildly
different appearances and purposes - yet all of them are
fundamentally alike on a genetic level.
Now consider the evolution of
racing engines - after all, this is a column about
motors, not domestic mammals. The vast majority of drag
race motors are offshoots from the Chevrolet V8 family
tree. And just as selective breeding has created dogs of
every imaginable size and shape, creative engineering
has produced a staggering variety of components. Yet
while dogs can still interbreed, many specialized engine
components are no longer interchangeable. |
I am
convinced that the two most misunderstood words in
engine building are "bolt on." In the days
when I built small-block Chevys with factory parts and a
smattering of aftermarket accessories, the term
"bolt-on" was meaningful. You really could
bolt on an intake manifold or change a cam using only
the wrenches, screwdrivers and sockets you could find in
any toolbox. Today it is more likely that you'll need a
lathe and mill to swap cylinder heads, intake manifolds,
or valvetrain parts.
Even Detroit has made life more
complicated for engine builders. For more than 30 years,
virtually every part in a small-block Chevy V8 was
interchangeable. Then in the mid-'80s, everything
changed. Chevy introduced new crankshafts with one-piece
rear seals, new blocks machined for hydraulic roller
cams and cylinder heads with reverse cooling. These
changes affected other parts, requiring new flywheels,
new torsional dampers, new valve covers, new water
pumps, new gaskets - and suddenly you had to be an
expert in esoteric part numbers to rebuild even a street
engine.
At the same time, the
aftermarket parts business was booming. The widespread
availability of CNC machining equipment, along with an
explosion in the number of people who |
