Technical Flathead V8 front mount distributor function.

I'm looking at a front mounted distributor from a 39 V8. I'm not familiar with these but it appears to me the centrifugal weight system retards the timing? And the vacuum controlled plunger allows mechanical advance when the intake vacuum is high ( part throttle) ?

 

PM GMC_BUBBA he is the Dizzy Maater...

 

Opps, I wrote it wrong.... The vacuum brake stops the centrifugal advance when the manifold vacuum is low... So I answered my own question

 

The vac brake adds drag to the centrigugal setup, so depending both on its adjustment and the vac level it can either slow rate of advance of pretty much stop it.
Gas is much higher octane than waybackthen, generally now you want to back it entirely off BY HAND so you don't pop the spring seat offa the do-dad, then screw it back in maybe 1-2 turns. You need this slight drag or the brake disc can float and allow some drift of timing. Be sure piston isn't stuck. If it is you can yank it out to clean and lube by running a tap into its top...I think the one I use is 1/4 pipe.

 

like when you crack the throttle on a v8-60 with dual carbs... could be your problem!