regardless of A/F ratios the dodgy primary emulsion tube in the FCR (no holes along its length) seems to be more effcient when the primary restriction is the main jet orifice at the bottom of the tube rather than relying on a fat needle to restrict flow at the top.
lineaweaver suggests that a main jet over 165 is indicative of a restrictive needle.
a 185 main may work well with the stock 200MAJ and perhaps produce a lot of tourque but as the primary restriction is then at the fat JD needle and not down at the MJ, peak power will be down. perhaps not enough to put JD out of business but if you want a bit more power its in there waiting to come out without sacrificing the tourque provided the MAJ is adjusted accordingly. check lineaweavers gallery for a dyno of some of the JD stuff.
if the carb does not have a removable MAJ I suggest making it a priority to drill and tap the carb to allow changing the MAJ
regards
Bushie
