ScottyP, dont take this as gospel but, I think the 44 rods are what you would call "very tunable" and they cover a wider range due to their design. Something about the taper and where it starts and ends and the amount of taper compared to the length. the other rods dont taper as much so the tunability witth the APT is limited (wit the others). That reminds me I need to get a set of them. LOL
How many jet sizes would they cover? (In percentages that is) I dont know. but they somewhat eliminate the need for a large assortment of different rods for the later carbs.
Cliff, do you mean to say that you can use them in the earlier carbs also? (when you say all carbs)