I began the run in process of my 353 today... 3 good tanks on the bench.

I opened the top 1 turn, richened the bottom a 1/2 turn and to get it up to a fast idle it took most of the idle screw to keep the revs and temp up.

From this short experience I can assume that the bottom is rich by default, I had good temps at around 5000 rpm and a steady rich fuel mixture flowing out of the pipe... yes my eyes were burning.

I expect my next step on track will require a considerable leaning of the bottom in order to get my idle gap to where it should be. Will keep you informed.

Fuel was Platinum AT Racing.