400 thermoquad vacume advance.

[JHolslin]

so, assembling my project car. I noticed the vac, line coming off my thermoquad goes to the fire wall to some small box then to the distributer.
what is the function of this and should I be able to blow thru it (Because it seams to be blocked).
Thanks for any info,

[flyinlow]

By pass it . Run carb to dist.

[71charger_fan]

Sounds like the OSAC valve which delays vacuum advance as an early method to reduce NOX emissions.

[JHolslin]

that's the one, thanks for the info. I just drove the car for first time this morning. its been sitting in a barn for the last 30 years. Blew a tranny line.
Thanks.