tri power carb set-up

[kelly theaker]

Recently i had the 69 carbs restored and found that yes they idled excellent but surged at highway speeds , checked for vac, leaks, ignition and dithering vac advance , all seemed excellent. The plugs ran a white or ash colour and suspected a lean condition , so i went up in main jet from 64 to 67 , it got better but still slightly noticable, once again checked plugs , a tan colour was beginning and could still feel a marginal surge , changed mains to 69 and all surging is gone. I had always a slight stumble off idle and read an article by Ken Anderson on 427 tuning in the fall of 95 , i was not able to find a contact for him , but the article suggested taking the accell shooter up in size and using ones with nozzles. He suggested stepping up in size , now the stock i am using is a 21 , he had suggested much larger - 35-37 which seemed far too big . Can anyone shed some past experience on tri-power jetting and nozzles . Ken's article stated the 69 s were being prepared for emissions and were leaned out to a point to pass . I am currently running 44 plugs .

[Joe R.]

Re: tri power carb set-up

Kelly,

You have done half of the suggested fix. Go ahead and try the 35-37 acc. squirter and you will complete the other half. Had to do the same thing with my 427.425HP and it solved my problems.

Regards,

JR

[Clem Z.]

changing the pump discharge nozzle

to one with tubes and going to a larger one is going to cause fuel pull over from the pump discharge nozzle at WOT causing the center carb to go very rich. we did the opposite back when we drag raced these cars by going to a anti pullover nozzle. we even tried pump nozzle check valves made from tungsten for the extra weight trying to keep it from lifting and allowing the fuel to flow. we jetted up all 3 carbs BUT we were running open headers. i still have the special plates that were used in the end carbs that could take screw in holley jet. i would try a #85 power valve to see what happens

[kelly theaker]

Re: changing the pump discharge nozzle

i am unsure of the term pullover , i thought the nozzle gave a more direct shot at the ? unable to remember the 2 round parts in the body, that the accell fuel stream hit and atomized . I was hoping to learn that yes or no you are heading in the right direction or ? Clem .

[Clem Z.]

Re: changing the pump discharge nozzle

pull over is caused by the air rushing thru the venturies passed the end of the discharge nozzles causing fuel to be siphoned from the nozzles independent of the pump action. the velocity of the air thru the small 2 barrel is so great that it lifts the check valve and the fuel keeps flowing so the nozzles feed fuel just like the boost venturies.