RE: ASP FS61 midrange problems
Now 1 of the things I have seen is someone bottoming out the lsn with out removing the hsn which damages the spraybar and or the lsn. Making it run rich in the 1/4 throttle range
IF you are an exp engine tuner an can't seem to tune it then yeah I'd change the carb.
I do love OS twin needle carbs try it an let us know