1971 was a one year only model of the TQ. It should still work. Correct gaskets used?
Float level? Do the metering rods stay down at idle [ they should ]?
Four turns out on the mixture screws seems a lot. Maybe one idle jet is blocked.
Correct gaskets, not quadrojet gaskets. I didn't check float level. New rebuilt so I just installed it as-is. Metering rods move up and down slightly at idle. Regarding mixture screws, engine stalls out when either screw is turned all the way in so i don't think idle jet is blocked. All good points though.