[ponchorob]

I just rebuild my 64 tripower and corrected and reinstalled the factory needle fuelinlet size back to 0.086 on the outer carb but ecently i read in a royal bobcat article that milt shornack often installed bigger fuel inlets against fuel starvation on full throttle but didnt mention the size...im puzzled now if i should increase to 0.101 but maybe theres a flooding risk but if i do...should the float level also be changed.....?

[Kenth]

Unless you´re running full throttle at 170 km/h all day long at the dragstrip you don´t need them.

The mechanical fuel pump will show its shortcomings long before the need for larger needle valves in the outer carburetors.

FWIW

[chrisp]

3/8 pickup in tank & 3/8 fuel line Carter 6907 pump with 3/8 fittings & 66 Tripower fuel line kit & you will be good to go.

[Dick Boneske]

Tri-Power setups obviously have three needle/seats. Quadrajets have one. Holley's have two.

At full throttle, isn't it logical that the three fuel inlets allow more flow than any single carb? I don't understand the attention given to needle/seat sizes on Tri-Powers. A more pertinent issue is the fuel supply and pressure available at the fuel block.

[carbking]

Adding some math to Dick's post:

Tri-power
(2) end carbs at 0.086 plus the center carb at .101 gives a total fuel valve seat area of 0.0196 sq in.

Q-Jet

1 fuel valve at 0.125 has fuel area of 0.011 sq in
1 fuel valve at 0.135 has fuel area of 0.014 sq in
1 fuel valve at 0.149 has fuel area of 0.0174 sq in

So even if one installs the .149 fuel valve in a Q-Jet, the tripower STILL has more fuel valve seat area (0.0196 to 0.0174)

If you throw the Carter AFB into the mix:

(2) optional 0.111 fuel valve seats has fuel seat area of 0.0194
(2) stock 0.101 fuel valve seats has fuel seat area of 0.0160

I do not have specs readily available on the Holleys, but I bet Dick is correct on them as well.

More folks are going to experience flooding issues on the street because of running fuel valve that are larger than necessary than folks that run out of fuel because of the valve seats being too small.

Money may be your best friend, but math and physics are your best economical friends

Jon