sounds pretty dodgey to me,

id say there would be a better way to do it, are you using a stock manifold and carby?

it should recieve signal from all four pistons

actually i think i know what you are using, there is a fitting with a big tube for the brake booster and a small for vacuum advance, both from te number 4 inlet

i am using the brake booster one but not the vacuum one, id like to plug that and use another outlet on the manifold for the booster (before the seperation to each piston, there is outlet on the passenger side just below where the carb bolts down)

but at the moment as i have a 32/36 weber, it has an outlet for the vacuum advance on the bottom of it and i am using that for the advance

I don't know for sure, but usually vacuum is taken:

1. From the ported vacuum on the carb (only has vacuum above idle).

2. From the plenum of the intake manifold. If you do this, you must disconnect the hose before timing the engine

I've seen "balance tubes" going from one cylinder to another. Maybe you could try that, and tee the advanced to both cylinders to even it out?

Got my truck running... sounds like a real beast. May drive it around the neighborhood tomorrow. But I've got a question. My vacuum advance get's it signal from the #4 piston intake runner. With it receiving a signal from only one piston will I have problems with the ignition advance? When it's running there's a loud ticking coming from the advance diaphram coninciding with the vacuum pulse of the cylinder. If this is a problem is there a mechanical-only advance distributor available for a-series?