... i used a quad originally off of a 305 on a 350 for a while and it seemed just fine, but this was before i knew or cared about jetting. Now, i want to use that same carb on a 4.3 v-6, due to my recent engine "cooking" experience which i may or may not discuss in another thread.....
If you're talking Q-Jets ... then the size of the 'jet(s)' is often not as important as the size of the Rod
There were multiple combinations of a given jet (primaries are easily removed, secondary are often a fixed dia. 'washer' type stacked into body)with a selection of rod size to meet the requirements of a given engine combo.
I have listings of over 200 separate combinations depending on make/model/year/trans/application/etc. and personally have over 70+ just rods in my Q-Jet parts box for jets/rods.
The jets are marked with a numeric code for size and the rods are marked and designated by a Two-Alpha (AA, AB, AC ...) or numeric code from Rochester depending on their location.
Next thing to consider is the 'Hanger' pitch-length. A given 'hanger length' will position the rod further up or down in the jet hole and affect fuel flow at different times in the throttle application or Secondary plate opening cycle - leaning or richening mixture as needed at different power bands.
So you may be able to just substitute a larger rod dia. with the present jet to reduce fuel flow and meet your tuning needs.
Investigate what you have now and adjust as needed/wanted to meet your needs.