Warren and all, Thanks for all the responses, Makes sense to me! So how do I tell which distributors these might fit?? Some are 2 piece pot metal w/clamping ring, others are 1 piece pot and the other 1/2 galv steel/tin. All have threads for the screw in vacum line to thread into. No parts #'s on any of 'em Dave S. ----- Original Message ----- From: "Warren Anderson" <wranderson@xxxxxxxxxxxxx> To: "list server" <Chrysler300@xxxxxxxxxxxxxxx>; "Dave Schwandt" <finsruskw@xxxxxxxxxxxxxxx>; "George Cann" <grcann@xxxxxxxxxxx> Sent: Friday, July 16, 2010 10:29 AM Subject: Re: [Chrysler300] vacum advance spec's > > > > > Dave and all, > > The numbers on the arm of the advance unit is the number of degrees that > particular unit > will move the breaker plate and advance the timing. > > Regards, > George Cann > > ----- Original Message ----- > Similar numbers are on Delco distributors but I did not know that they > were on Chrysler parts. Good to know. > > As mention, number is in degrees of breaker plate travel (spark advance) > and that will be 1/2 what can be measured at the crank pulley. So, 12.5 > arm will relate to 25 degrees advance measured on crank pulley. At idle, > with full manifold vacuum to chamber, base timing set to say 10 degrees > BTDC, 12.5 arm distributor and 35 degrees should show on balancer. At 2500 > RPM, mechanical advance should be all in or close to and the reading > measured will be usually above 45 degrees. Multitude of different, > workable calibrations, custom fit and OE spec. All that lead is to help > burn light throttle, lean cruise, late burning mixture. > > Warren Anderson > > Sedona,AZ > > > [Non-text portions of this message have been removed] > > > > ------------------------------------ > > To send a message to this group, send an email to: > Chrysler300@xxxxxxxxxxxxxxx > > > To unsubscribe from this group, send an email to: > Chrysler300-unsubscribe@xxxxxxxxxxxxxxx > > > For list server instructions, go to > http://www.chrysler300club.com/yahoolist/inst.htm > > For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups > Links > > > > ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: Chrysler300-digest@xxxxxxxxxxxxxxx Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/