STROMBERG BIG 97 PRIMARY CARB PLAIN 250CFM

Description

The BIG97 Primary features
250cfm airflow with
significantly improved fuel
circuits, and provides ported
vacuum for your modern
aftermarket distributor. It
can be used on its own, in
multiples (with direct or
progressive linkage) or as
part of the BIG97
Tri-Power.

55%
more airflow
BIG97s move up to a 1.175in
venturi with super-efficient
20 degree entry angles. The
accelerator pump discharge
jets are smaller and well out
of the booster airflow. And
flared exit cones build power
by slowing the mixture down to
reduce turbulence into the
manifold plenum. The result?
250cfm per
carburetor.

New
power valve circuits improve
fuel conditioning
Feeding top end enrichment
directly into the emulsion
tubes, BIG97 Primaries
significantly improve fuel
conditioning for more top end
HP on less
fuel.

New ‘early
plenum effect’ boosts top end
power
Allowing
all cylinders to draw from
both barrels gives you
dual-plane drivability with a
single-plane style top end
horsepower.

Ported distributor
vacuum
Switch in
the brass plug (supplied) and
connect your distributor to
improve combustion efficiency
in cruising mode. You’ll run
smoother and cooler, with more
torque and better fuel
mileage.

BIG
S-jet twin-ball inlet
valve
Accepts
big diameter 5/16in hard line
(regular 97s take only 1/4in
line), plus regular Stromberg
fuel
fittings.

All
Genuine 97!
Everything that makes the
Genuine Stromberg 97 so
popular is built into the
all-new BIG97. From the cast
iron base to the reinforced
air horn casting and
everything in
between.

Runs
out of the box
BIG97s come ready to run
with the following jetting
(see below). As with any
carburetor, rejetting may be
required for other
applications, high altitude,
local gas, ethanol content and
more. A wide range of jets and
power valves is
available.

BIG97
Primary jetting:
Main jets 0.056in Power
valve #65 Accelerator pump
valve #60 Note: This jetting
is designed for Primary use as
part of the BIG97 Tri-Power.
Smaller jetting will be
required when using BIG97
Primaries in
multiples.

• All
  Genuine 97 on the
  outside
• Totally new on
  the inside
• BIG 250cfm
  airflow – 55% more than a
  regular 97
• New power
  valve circuits improve fuel
  conditioning
• New
  ‘early plenum effect’
  boosts top end
  power
• Ported
  distributor vacuum adds
  mid-range torque
• BIG
  S-jets accept 5/16in hard
  line
• Runs out of the
  box