Re: Im going to run a NGK B5HS spark plug....
fdsu , your needle only effects throttle response between 1/4 & 1/2 throttle. It goes something like this 0-1/8th throttle is idle air (mixture screw not usually on these carbs), 1/8th-1/4 = idle jet, 1/4-1/2 = needle jet and 1/2-wot is main jet. To check proper needle adjustment you'd need to do throttle chop / plug checks at 1/4-1/2 throttle. On plugs you want to run the coldest plug that doesn't foul. When running too hot a plug you may have detonation (preign) w/o knowing and reduce longevity considerably w/ no gains.