I have been driving my 60 348 tri-power for a while. The idle and off idle performance is poor and acts lean. Idle screws do little and are out 2-1/2-3 turns. Total timing 34*. initial 14-15*, idle manifold vacuum hot is about 8"hg, and swings +/- with the speed variation. Yes the throttle plates are open quite a bit so likely close to the idle transition hole effectiveness.
I looked for and tested for(carb cleaner around the bases) air leaks) nothing found.
I pulled the center carb and everything looks OK. All fuel restrictions are basically OEM, mains are 60's.
My initial reaction is to up the idle fuel tube orifice .003-.004 and up the upper restriction about the same (passes fuel and air emulsion). Before I do that I wanted your opinions, and what you have had to do after adding a larger duration cam. FYSA, this was needed on my 409/425 after installing a bigger bump stick.
TIA Robert
I looked for and tested for(carb cleaner around the bases) air leaks) nothing found.
I pulled the center carb and everything looks OK. All fuel restrictions are basically OEM, mains are 60's.
My initial reaction is to up the idle fuel tube orifice .003-.004 and up the upper restriction about the same (passes fuel and air emulsion). Before I do that I wanted your opinions, and what you have had to do after adding a larger duration cam. FYSA, this was needed on my 409/425 after installing a bigger bump stick.
TIA Robert