im running a dynamite mach 2 .21 in my buggy, for an economy engine this thing hauls !!!!!, it seems after i come off a high speed run it will idle a little fast for about 3 to 5 seconds before it comes down, and then it will idle smooth forever, the pinch test is 3 to 4 seconds, if i let it idle for about 5 to 10 seconds or so and then hammer the throttle, it's sluggish but it clears out and goes, i can get it to go to an instant idle after i come off a high speed run if i fatten up the low speed to about 7 seconds on the pinch test, then it seems really sluggish when you hammer it after a 5 to 10 second stop, i have been serching on this site for two days and im getting mixed reviews, it just seems like this engine has to be really fat on the low end to run properly, maybe thats how it has to be,

Your symptoms seem to point towards a lean high speed and rich low end. Try leaning the low speed needle 1 to 2 hours and richen the high speed needle 1 to 2 hours and run it. Your idle will probably be a bit high but will not drop down. Now you can lower the idle speed a bit.

do you have a throttle return spring attached, if not that is normal from my experiences... Sounds like tyou have the LSN tuned well, may still be a bit rich on the HSN that would cause you to get a pause when you hit the throttle try leaning it 1/8 of a turn and see how your throttle response id... also make sure you have the correct size exhaust pipe...

i do believe you were correct; i had to lean it a total half turn on the low speed to finally get it, now it doesn't hang on the high idle or load up after 15 seconds of idle, it's a little snappier of line also, i thought it was pretty good before, i bet it's going to do better at the track as far as spooling up out of corners, thanks again