Tune up help needed(pics posted) Update

[rjewkes]

sounds like the the transmission spark control deal attached to some wires that end up in the doors and a speed sensor.

either way some just bypass this.

[fordman]

i don't think he has that on his truck. those came out in 72 i think. i've never seen one of those in door things on a 70.

[peanutman]

It's some kind of vacuum control for the dual vac advance dizzy. has three ports, 1- larger that goes to intake and two smaller, one goes to carb and one goes to dizzy. If you blow or suck on ports while compressing spring it controls the three port with different levels of passage. Has somthing to do with controlling the vac timing advance at different rpms.

No power runs to this it's just a variable control valve, i just need to know what it's called and i guess you would use a vac gauge to adjust it or just adjust the spring tension until the engine runs better.

[peanutman]

Here is what this valve looks like.

[peanutman]

Well i found what out this valve is. It is a deacceleration valve, It advances the timing thru the vac system from the intake to reduce emissions when you let off the gas. Talked with an old ford mechanic today and he explained that they used to disconnect them when they went bad, which is apparently what happened to mine at some point and rebuilding the carb increased the vac and brought my bad valve to light.
Just in case if anyone else runs into this problem the mechanic said to plug the back port on the dizzy and run my vac advance to a vac port on my carb and plug the port coming out of the intake, said it should run better than with it.

Napa said this valve is no longer available. now my truck runs great.