i never change anything when swapping from one size to another all the q jets are pretty lean jetted anyways, especially the later years they are,
the secondary rods you can check without doing anything except rmeoving the small flat head blade screw that holds the secondary rod hanger on the top of the carb between the two secondary air valves cant miss it
jut pull the screw and lift the hanger up with the two rods, straight up
are two-letter codes on them like AA or BC etc.
are charts online etc to decode them, certain ones are better than others of course.,
i collect any and all q jet carbs i come across either to go through or for parts only. so i have amassed lots of trays of parts and lots of carbs over the years, and i only run q jets on my gm v-8 engines
there are billions of informational pages out there on the web for these carbs. lots of info, you cna find out anything about them.