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1966 Chevy Chevelle - Moving Cheap!

How to run 12s with a $200 4.8L LS and a Little Squeeze

By , Photography by Mike Morgan,

CAM SPECS
Comp Cam 269LR HR-112 Duration (Advertised) Duration (0.050) Lift (inches) Lobe-Sep. Angle
Intake 268 219 0.607 112
Exhaust 276 227 0.614 NA

NOS CHEATER JETTING NUMBERS*
Nitrous HP Nitrous Jet Fuel Jet
100 0.047 0.040
150 0.063 0.057
180 0.073 0.065
210 0.082 0.076
250 0.093 0.085

*These numbers are predicated on a base fuel pressure of 6 psi and 950-psi nitrous pressure. We also retarded timing and used cold plugs to help with the 150hp shot.

TRACK TIMES
Conversion:
Eighth-mile e.t. x 1.57 = quarter-mile e.t.
Eighth-mile mph x 1.24 = quarter-mile mph
Run/Time 60-Foot 330-Foot 1⁄8 e.t. 1⁄8 mph 1⁄4 e.t. (est.) 1⁄4 mph (est.)
1) 5:18 2.331 6.028 8.994 83.68 14.12 103.76
2) 6:12 2.301 5.980 8.951 83.37 14.05 103.38
3) 7:55 2.125 5.682 8.588 84.98 13.48 105.38
4) 5:12 2.055 5.622 8.514 85.37 13.36 105.86
5) 5:33 2.020 5.587 8.478 85.44 13.29 105.95
6) 5:52 2.020 5.612 8.506 85.35 13.35 105.83
7) 6:13 2.035 5.153 7.730 94.54 12.13 117.23
8) 7:02 1.959 5.072 7.668 93.75 12.03 116.25
9) 8:22 1.974 5.118 7.684 95.51 12.06 118.43

Descriptions: Weight with driver (3,645 pounds)
1) Hesitated badly on the starting line
2) Drove car off the line, but still poor 60-foot; cooler air, no changes
4) Richer accelerator pump cam and nozzle, more timing, purple vacuum secondary spring
5) No changes from 4
6) No changes from 4 and 5
7) First nitrous run: spun badly off the line; NOS Jetting: 63 nitrous / 57 fuel
8) Second nitrous run, no changes: delayed nitrous start
9) Third nitrous run: tried lower 19-psi tire pressure, hit nitrous on the line, spun, lifted

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