71 302 vacuum advance, 2 port, what does it do?

[Paul G]

My 2 port vacuum advance can does not hold vacuum in either port. 2 port replacements are available, but I only see single port replacement complete distributors. Is there any reason to keep the 2 port other than being factory correct?

 

[Sheriff41]

One side advances the timing and the other side retards it. This was an attempt to satisfy emissions standards. A single source advance unit works well.

 

[Paul G]

Switching to a single source advance, Would you just bypass the temperature switch, or plug the unused port on the temperature switch?

 

[Sheriff41]

Bypass the thermostatic control valve is my technique.