As Jay said, the vacuum advance is part of the total timing, but for a street car 45 + degrees will be fine at partial throttle or cruise and give you significantly better fuel economy. Roughly 20%. As soon as you approach WOT the vacuum advance will drop out and you will then be on the mechanical curve only.
thanks guys , clears it up

Quote from: gdaddy01 on August 14, 2015, 06:35:09 AM

do you plug the vacuum line back in and then the timing goes up to about 45 to 50 degrees ? the vacuum is not part of total timing ?

 

The Duraspark distributor pickup works directly with the MSD, just connect the wires like they show in the MSD instructions and go. 

You can get the stock Duraspark distributor recurved by Faron, who posts a lot on this forum.  Hopefully he sees this.

I'd defer to MSD on the coil.  If the MSD6 instructions say you can use the Blaster SS coil, should be no problem.  The instructions should be available on MSD's web site.

I like to set the ignition timing as total timing, rather than an initial value.  After you have the distributor curved you will know what RPM the advance is fully in at.  Disconnect the vacuum line to the distributor and rev the engine up a little past this RPM value, and then set the timing at 36 - 38 degrees for stock heads.  Then let the engine idle down and see where your timing is at idle.  Most of the time you'll see values in the 12-16 degree range.