the plates I have have a 34r-6153-b number. they also have a 35 stamped on them that used to indicate orifice size but it seems holley may have gotten cheap on the re-pops and one size fits all. anyhow, that's no big deal. the largest orifice is .093", which I think may be ideal, but if it isn't those orifices can be opened up. the 6-32 set screw thing gives you options. one option is drilling and tapping the power valve channel restrictions for the 6-32 like the race carbs. doing this will allow you to do the power enrichment from the power valve, which is it's job, and not rely on the main jets for power enrichment which is not their main job. think of the carb as having and idle circuit, cruise circuit (jets), and power circuit (power valve channel restrictions). I think using the main jets as the sole source of enrichment just muddies everything up. looking the 1971 race bulletin it shows using #69 main jets on the primary side. that's pretty large for the size of those venturi and throttle bores. bet they weren't looking at playing with the power valve channel restrictions.