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Old 10-20-2012, 12:35 PM
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Agreed, removing the power valves (replace with a PV plug) and rejet to 78 pri and 80sec jets will work well for dyno testing and drag race running only.
Lock out the timing and set to 36deg BTDC to get the idle set up
Then reduce timing to 26deg BTDC (locked) for dyno testing @WOT. Adjust timing and jetting as required on the dyno. 26 to 32deg range.

No ECU timing control is required. just disable it.

Once you ahve sucessfully tuned it on the dyno. (Timing-jetting) you can use a manfiold vacuum gauge on the carb base to read the vacuum created on the carb base by the blower pulling @ WOT max power rpm.

If this vacuum reading with a vacuum gauge on the carb BASE is less than 10" @WOT,,,, use a 10.5" power valve.
install 10.5" rated power valves and reduce pri jet to a 70 to 74 jet as required. (6 to 8 jets leaner than the best jet found testing without a power valve)

You will need a bunch of holley main jets and two holley power valve plugs for dyno testing.
a pair of 70 72 74 76 78 80 82. jets will cover it. Do not get greedy on the timing under boost.
Start rich on the jetting and work leaner while watching plugs, BSFC, dyno AFR and or AFR from a O2 sensor/gauge.
Use a purple or yellow holley secondary spring. Make sure the vac housing is sealed to the carb body ( little o gasket)
and the vac sec diaphram seals so the vac sec operate correctly.

This motor needs two 750cfm double pumper blower carbs. This motor does not need a ECU to congtrol timing.
All it needs is a locked distributor and a Boost retard ignition box. (Crane Cams, MSD)
real simple.

Last edited by F-BIRD'88; 10-20-2012 at 12:50 PM.
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