Jim Smart
July 1, 2003
Photos By: Julio Mayen

No. 1
After three warm-up pulls, we're doing a 6,000-rpm pull to establish a baseline to work from. We're going to follow this pull with a series of pulls that involve a simple swap and finite tuning.

Cylinder HeadsAFR 185
Compression Ratio10.0:1
Intake ManifoldEdelbrock Victor Jr.
Carburetor/Jetting/Adjustment650-cfm Race Demon w/spacer
Camshaft TypeComp Cams 282 Hydraulic Roller
Rocker-Arm Ratio1.6:1
Ignition Timing34 deg. BTDC (full advance)
Header Type & Size13/4-inch long-tube headers
ChangesNone
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,300426.60.44612.00
6,100480.50.51310.77

No. 2
With four pulls behind us, we have baseline numbers to work with. Our goal is 500 hp, with roughly 420 lb-ft of torque. To get there, we will have to make changes and adjustments. We decided to swap the Race Demon's air bleeds. Take a look at what happened with just a finite carburetor adjustment.

Cylinder HeadsAFR 185
Compression Ratio10.0:1
Intake ManifoldEdelbrock Victor Jr.
Carburetor/Jetting/Adjustment650-cfm Race Demon w/spacer
Camshaft TypeComp Cams 282 Hydraulic Roller
Rocker-Arm Ratio1.6:1
Ignition Timing34 deg. BTDC (full advance)
Header Type & Size13/4-inch long-tube headers
ChangesChange carburetor air bleeds
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,300427.80.45911.63
6,300487.80.48111.60

No. 3
If you watch Elvira's 331 dyno session long enough, you'll see that change often comes from minute tuning adjustments. Look how much power we gained from removing the phenolic four-hole spacer and installing a Wilson Manifolds billet 11/2-inch tapered spacer. Timing and fuel mixture remain the same.

Cylinder HeadsAFR 185
Compression Ratio10.0:1
Intake ManifoldEdelbrock Victor Jr.
Carburetor/Jetting/Adjustment650-cfm Race Demon w/spacer
Camshaft TypeComp Cams 282 Hydraulic Roller
Rocker-Arm Ratio1.6:1
Ignition Timing34 deg. BTDC (full advance)
Header Type & Size13/4-inch long-tube headers
ChangesWilson 11/2-inch tapered spacer
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,300431.00.49010.85
6,300491.00.46911.83

No. 4
Prior to the fourth pull, we realized we had maximized the potential of our 331 for horsepower with the Victor Jr. intake manifold. Although we fell 9 hp shy of our goal, our horsepower-to-cubic-inch ratio came in at a very respectable 1.48 hp per cubic inch. John and Steve applauded us on the performance of our 331 and stated that their Chevy 350 they have used as a benchmark for all small-block engines makes only 1.42 hp per cubic inch. With this in mind we felt much better and decided to find more power on another day. At this time we decided to do a comparison by using a more streetable intake manifold and installed an Edelbrock Performer RPM to run through the paces. We knew we would lose horsepower but the dual-plane should make up for it with torque.

Cylinder HeadsAFR 185
Compression Ratio10.0:1
Intake ManifoldEdelbrock Performer RPM Air-Gap
Carburetor/Jetting/Adjustment650-cfm Race Demon w/spacer
Camshaft TypeComp Cams 282 Hydraulic Roller
Rocker-Arm Ratio1.6:1
Ignition Timing34 deg. BTDC (full advance)
Header Type & Size13/4-inch long-tube headers
ChangesManifold swap to Edelbrock Performer RPM Air-Gap
and Wilson 1-inch carb spacer
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
4,700427.10.45311.26
6,100471.10.53410.30