Vacuum advance Distibutor ??

I'm currently running an MSD Pro-Billet distributor that's locked out with an MSD Digital 6 box. I'd like to replace that distributor with a distributor that I can run locked out, and still have a functioning adjustable vacuum advance.

I'm running 35* timing on the Pro-Billet, but want to add more advance using the vacuum feature for street and highway use.

Any suggestions on which distributor would work best. I see a bunch of ready to run distributors, but would like to keep my MSD Digital 6 box.

A laptop adjustable ignition would be nice, but I need the vacuum advance feature too.

Me thinks your want miracles, if it is locked out how can the vacuum advance work
I think you need a ECU that can use manifold pressure, throttle position sensors and maybe some other sensors to do what you want like EFI systems use to manage ignition timing

Couldn't you use a stock distributor with one of those advance limiter plates or just weld up the slots in the centrifugal weights and still allow the vacuum advance to move the plate?

6 AL 2 programmable ?

this can easily be done. Get a street distributor, (or stock) Lock down the centrifugal weights (weld?), then use the vacuum advance. The vacuum advance, advances the relector/pickup (or points if your are really old).
If you do this the rotor tip needs to be pretty wide, your going to add 45-50 degrees of ignition timing without the rotor advancing. That works out to 22.5-25 angle of degrees and with a terminal every 45 degrees, misfires might be a issue.

Joe

edit MSD sells a adjustable rotor that will help with phasing.
part # 84211

I have the MSD adjustable rotor in there already. My phasing was so far off to begin with. Also, the 2 wires coming from the MSD Pro-Billet were swapped from the manufacturer, which didn't help. Once I got all that sorted, I was unable to get stable initial timing as it was bouncing with the light springs being unable to hold the mechanical advance steady at 900 rpm. That's when I experimented with locking out the distributor.

Now that all those issues are resolved and the car being easy to start hot or cold with 35* of timing, I rephased the rotor to line up at that timing setting. I assume I will only be adding 10* to 15* of vacuum advance to it, not the whole 45* or 50*, so there will be much less change in relation to the rotor tip and the terminals.....Right?

I don't have the newer programmable MSD. I'm assuming a programmable ignition system would need input from both a MAP sensor and a TPS to replicate a vacuum advance curve. Can anyone who knows about that sort of stuff confirm that? Rich or Andy would surely know.

The MSD E curve distributor will do what you want but they don't make a big block Mopar version. I used a SB E curve on a 427 inch small block that was set up for road racing. It worked great back in the day. These days I'd use a Sniper and Hyperspark.

Andy, will a MSD grid do what he needs with his current MSD parts?

yes, your just going to add another 15-18 degrees. being able to advance the rotor should clear up any misfires.



Joe