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4 Bob knew there was a bit more potential in the engine and suggested we add a spacer to increase plenum volume to the intake. The 1-inch open spacer added 2 lb-ft of torque at the peak of the previous test but moved the new torque peak down to 4,500 rpm. Compared to the earlier 4,500-rpm peak, the gain was 11 lb-ft. The same can be said about hp at the old peak. We saw a 2hp gain, but our new peak was at 6,200 with 416 hp.