Vacuum advance hose collapsing?

[MrSony]

Is it supposed to? On my '70 Ford 429, the old hose was mushy up near the carb and started to collapse shut on anything other than 800rpm idle. I changed it to a hard but flexible plastic hose used for emissions systems on newer cars and the car does perform better. The OD of the hose was the same size as the OD of the vac advance nipple so I took a lighter and heated the hose up pushed it on (carb side and nipple side, don't worry I took the hose off away from the carb before a fire happened) and it flared the end out and fits snuggly. Now, I'm new-ish to distributor type cars... is and this is probably a stupid question, but is the hose supposed to collapse? And upon starting an engine for the first time after a rebuild (my Buick 350 w/ HEI) should it be hooked up at all?

 

[87BlazeLS]

Well I might be able to help here. when installing my 350 sbc crate motor in the MC the paper work
from Gm performance said to not use the vac advance from the HEI dist. After I got everything installed and running I tried it with the vacuum advance hooked up and it was much better and smoother
on idle. So I've had it hooked up ever since.
So the initial timing needs to be set with the vac advance disconnected. Nipple on carb base plugged. This should be on a ported vacuum slot.

This means no vacuum is present at idle and as you tip into the throttle the advance starts to kick in.
The hose should have a strong wall thickness. And should not collapse. Check for proper connection
at the carb.

 

[MrSony]

Thanks man.

 

[SoFloG]

I've seen this debate for years vac advance to ported vacuum or manifold vacuum? I personally run it to ported and use the other port for the shift solenoid on the trans. Definiteley always hook up the vac advance the hei were meant to function like that. I had a mech advance msd distributor on my race motor with a 7al2 ignition,and i swear the car ran better with a stock gm hei and upgraded coil.