Jim Smart
July 1, 2003
Photos By: Julio Mayen

No. 9
Having achieved the 500hp objective, with torque holding steady around 437 lb-ft, Julio and John decided to fine-tune Elvira's 331 for real-world performance, with components that would make Elvira less temperamental and downright wicked. Here's where they headed next.

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
ChangesSwitch back to AFR 185 heads, 1.6:1 rocker arms
for reduced valve lift, and hydraulic roller lifters.
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,300432.30.46611.76
6,300488.60.46011.93

No. 10
What we learned with the 10th pull was the value of the AFR 185 cylinder head. It gets us within 17 hp of the AFR 205 head, equipped with larger ports and valves. So how do we close the gap without changing heads? How do we close the gap, working our way back to 500 hp and a significant improvement in torque? John Da Luz made minor adjustments to the Race Demon carburetor. Julio swapped the Wilson 11/4-inch open spacer for a Wilson 11/2-inch billet-aluminum spacer with four tapered ports. Timing was kept at 34 degrees BTDC. Here's what Elvira did.

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
ChangesMinor carburetor tuning. Swap Wilson 11/4-inch spacer
to 11/2-inch spacer with tapered ports.
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,200432.80.45011.92
6,300496.50.47711.75

No. 11
Look, Ma, no hands! Steve Bruel elected to run the engine again after a brief cool down to see what the dyno would reveal. Without touching the engine, look what happened. A warm engine makes more power than a hot one, and this is a case in point.

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 Ratio1.61
Ignition Timing34 deg. BTDC (full advance)
Header Type & Size13/4-inch long-tube headers
ChangesNo changes, just a cool down.
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,200433.90.42212.08
6,300501.90.46811.82

No. 12
As you can see from Pull 13, stepping up to a 750-cfm Race Demon made virtually no difference in performance numbers. John Da Luz downsized the jets for an 84/90 combo. Spark-plug gaps were increased from .035 to .040 inch. Do you know what happened next?

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
ChangesDownsize the jetting. Enlarge spark-plug gaps.
RPMPeak HPPeak TorqueBSFCAir/Fuel Ratio
5,200433.60.40513.06
6,300504.80.44612.57