FRUSTRATED!!!

Kg/hr/barrel at warm idle = ?
RPM at warm idle = ?
warm idle timing = ?
status/behavior of advance mechanisms = ?
distributor type = S159A or S159B?

 

Way too high -- should be ~3.5 Kg/hr. You either have some cylinders not really contributing at idle, or your Synchrometer is miscalibrated. Pull a spark plug wire off 1 at a time at idle -- you should note the miss on each cylinder if it's really contributing something at idle.

A little lowish, but not unacceptable

Too much for a US S159B 308 distributor -- should be ~7 deg BTDC
OK for a S159A distriibutor

At a minimum, with a timing light just make sure that both distributor's advance increases/decreases smoothly with RPM increases/decreases. Also, there's a mark on the flywheel for checking the total advance at 5000 RPM (although if you're at 16 deg BTDC now with the S159B distributors it will be way off)

Should be shown on the metal label rivited to the dist body

You haven't ruled it out yet, but if the quicky visual inspection described above looks OKish, it's probably not the cause of your problems -- the 7 Kg/hr at idle and resetting the idle advance (if you have the S159B distributors) are the first areas to address IMO.

 

i got rid of my stumble by going to idle jet size 60

pull your idle jets and see what number they are, you can pull these without removing the carbs.

 

ok, good on the jets.
check to make sure each accelerator pump is working - crack open the throttles at each carb and look down carb throat and see spray form accel pumps.
re-tighten the 2 screws that hold on the choke covers -even tho you are not using the chokes, these covers should be tight, mine were warped so i had to match the castings by sanding down the covers to ensure a tight fit onto the carb body.
since you rebuilt the carbs, i would re-torque all the carb hold-down nuts at the base of the carbs to ensure no leaking of air there. also re-torque each of the 4 or 5 screws holding down the air horns (not the venturi nuts that hold on the air cleaner, but remove the venturis and tighten down the air horn screws.)

 

I second Steve's comments on the flow and advance being way off. Reset that flow rate and the advance at idle and it should improve things. Before you start changing jets, get those things corrected first.