DeTomaso Mailing List: February 99, Message #148

Tom,

Yes.

Some distributers have both advance and retard capabilities. These will
have two vacume thingies on the vacume control. One closest to dist will be
retard, outside one will be advance. Depending on your smog situation...
you may use both. Consult factory vacume manuals for your application.....
  Most people only use one. Advance.

Put a hose on the outside one and blow (sucking gets mouthfull of
guck....potentially.) If you can blow air...bad diaphragm. Visit parts
store....

Carb ports: two types, full vacume all the time (intake manifold) and
"ported" vacume. This is the connection, on Holleys, on the metering block.
No vacume at idle but when the throttle blades open, vacume is "ported" to
this connection.  Fords typically use ported. 57 Chebys use full.

Steve