I've never heard that about the lifters, I had a 1970 T/A motor that I replaced the cam and lifters with a solid lifter cam. I should have save them but that was back in the mid 1970s
The NHRA tech sheet on those motors listed the lift and duration as the same for the 1968 to 1971 340 4 barrel motors
I wonder if they have the same part number as the 1969 440 6 pack low taper hydraulics lifters?