Generally seaking you would want to shift the motor at 3-500RM above peak HP. Since it is a powerglide car my guess is the converter is WAY wrong for the combo. What is the shift recovery rpm after the 1-2 shift? What is it when you run the RPM up higher? How much faith do you have in those dyno numberers? Ideally that car should want to be shifter at 72-7400 to see it's best ET. But you don't have a ton of gear either. If it were mine I would be looking at the converter real hard and possibly gearing.


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