Sandbird (12/10/2018)
The outer diaphragm goes to the manifold vacuum at the distribution block at the base of the 4000 carb. The inner most diaphragm on the distributor housing gets ported vacuum from the carb at the connection just above the spark control valve. They should hold a vacuum, The diaphragm that uses ported vacuum only requires a few inches to operate. If it's new I would just put it on and check it with a timing light.
Ah ok whats throwing me for a loop is the manifold vacuum I got home and dug through my digital copies of service manuals the 56 supplemental manual for the holley 4000 is where I see the manifold vacuum goes to the outter most canister which is known as a surge diaphragm and it appears the outter diaphragm has a spring while the larger diaphragm has no spring that explains why it flops in and out so easily with no resistance. Pulling out on the advance arm and putting some light vacuum via mouth to the port it pulls so it looks all good.
Only thing holding me up now is I got my box out from 2 years ago from the parts I bought to put the original stuff back on the car but was put on hold finding the last few hard to find pieces, I found out now my choke control inlet tube is defective or wrong. The bag says inlet tube 1956 with a part number of B6A-9820-A but the tube in the bag has a tapco tag on it that says 56 thunderbird 9820-B and the thing isn't even shaped right. The tube is supposed to be vertical so when you plug it into the elbow on the heat tube its supposed to wrap around the intake and straight up into the bottom of the air horn of the carb. This thing if you hook it up properly would be pointed at the spark delay valve and its heavy steel. I decided to order another one from Larrys this time at a tune of $20, its listed on his site as a p9820-B the -A comes up as a 55 with a different shape so hes not using OEM part numbers which my 56 with 292 would be a 9820-A not a 9820-B.
None the less I hope larry can get me the part before this weekend as I really want to figure out how to get the choke tube that's broke out and figure out how you get the new installed. I look at the new tube it has a raised lip so it looks like you have to work it in through the exhaust port then line it up and tap it back into place till it stops. I need to hit my shop manuals again cause I already looked once and there was nothing in them about replacement of the choke tube.
1956 Ford Fairlane Town Sedan - 292 Y8 - Ford-O-Matic - 155,000 mi