My 1406 carb hesitates (a little) if I stab it to the floor below ~3500 rpm. Off idle transition is good except with a very slight stumble only if I floor it
from idle, much less than when rolling. Motor pulls clean to 6K, haven't tried taking it higher. I think it is hesitating on the transition to secondarys.
Motor is a 350 chevy in an 83 S10, 487X heads~9.5-10:1 cr, comp xe274, RPM air gap intake, HEI w/msd 8501 kit, spiral core wires, NGK (br6fs) plugs gapped to .040, hedmann shorties w/2.5" duals, 700r4 trans w/stockish converter (2k stall maybe?), 4.10 gears. Timing is 15 initial/35 total (in by 2500) +12 for vac can (full vacuum not ported). Vacuum is 15.5" at 800 rpm.
I've tried different springs, moving the pump arm linkage, jetted from stock to .104's in all corners with a 75-47 rod and 8" spring, upped the squirter from .031 to .033 and yesterday I rebuilt the carb. The hesitation remains.
Currently running .100 w/75-37 rod and 7" spring in the front, .101 in the rear, .033 squirter with the linkage on the inboard hole.
I noticed that the 1405 calls for a .028 squirter stock (thought those were supposed to be dialed richer) and was wondering if it would be worth trying the .024 squirter I got in the kit? (longer duration shot?)
Also wondering if a looser converter would help (it's on my wish list anyways)?
Am I off base that this is a secondary transition problem?
Anything else I have overlooked?