We use a restrictor plate with interchangable venturi which vary in sizes from 1.300 1.200 1.100 and 1.000. Previously we ran 1.200 to make the car run 7.50 in the 1/8th mile when we changed the valve body with the 1.200 it ran 7.28 in the 1/8th. We ended up putting 1.000 to make the car run 7.50 in the 1/8th. This also picked up the 60ft time from 1.59 to 1.56.
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