ok, the stumble is completely gone after engine is at operating temp. (180*+). i tried the 35 squirter first and the stumble would'nt completely go away, so i tried 40's and stumbling issues are gone. the leaner jetting also made a world of difference as now from a 15-20mph roll in first gear i can hammer it and the 325/50 mt/drag radials fry thru 1st and sometimes all the way thru 2nd gear@7000rpm. this indy headed 408 is finally coming together. its becoming a real beast.