We install a pair of AFR
CNC Ported Magnum BBC Heads
Words by Darr Hawthorne
Photos by Zak Hawthorne
It was back to JMS Racing Engines in Monrovia
as the parts continued to arrive for the re-build of our
Project Street F/X Big Block.
These heads were designed to
optimize low and mid-lift airflow, while still generating
impressive peak figures with a primary operating range
of 2500 to 6800 RPM. Mamo emphasized that these cylinder
heads maximize the entire flow curve, not just the
big peak numbers.
It's really no secret in engine building science that getting
air into and out of each cylinder quickly and efficiently
is probably the most significant change you can make to your
engine. For over thirty years, one of the truly well known
names in racing cylinder head technology is SoCal's Air Flow
Research in Pacoima, CA.
While talking with Tony Mamo, the principal port designer
at Air Flow Research about our engine build, he asked a lot
of questions about our camshaft, carburetors, intake manifold
and final usage of the 468 cubic inch motor.
Since we will be drag racing and occasionally be driving the altered wheelbase
Chevy II on the street to a few local car shows and for Friday night cruises,
Tony recommended a pair of AFR 315cc Fully CNC Ported Magnum BBC Heads.
||The camshaft grind (CB 4315/4271
R112) from Comp Cams with an advertised valve lift
of 0.746, intake duration of 310 and exhaust duration
of 315, the AFR heads would retain the Ferrea valves
that ship with the 315 CC heads. Mamo felt that with
this cam they wanted to upgrade to a Manley Spring
The heads are beautiful with
extremely smooth runners and significant increase in
runner volume over the stock oval port. The new AFR
heads include Competition 5-angle Valve Job, 2.250-inch
stainless steel intake valves, 1.880-inch stainless
steel Exhaust Valve, 1.550-inch OD Roller Dual Valve
Spring with dampener and bronze valve seats.
When the new AFR heads were delivered to JMS Racing Engines,
just about every guy in the engine shop came out to take
a look. Owner Mike Johnson had not seen a set of the 315
CC heads yet and based upon the specs feels that our new
combo should dyno strongly at 600+ horsepower.
Before the New Year we will begin our final build and then
test on the JMS dyno.
Air Flow Research
10490 Ilex Avenue
Pacoima, CA 91331
3406 Democrat Road
Memphis, TN 38118