I am about to make my way towards a purchase of a new dizzy as they are called. I would like MSD or Accel...nothing else...my question is what is a Vacuum Advance and a Machanical Advance??? The Accel I want ONLY has Mechanical but the MSD I want has BOTH....whats the difference between the 2?

Thanks Much.

 

Centrifugal advance increases RPM increases. Vacuum advance increases as vacuum increases while cruising. For a street car you want the one that has both vacuum and centrifugal advance.

 

Centrifugal would be the mechanical right? Just verifying. Thanks alot.

 

Pretty much.

That's all assuming that you're running a non-computer carburetor. You need something different if you have fuel injection or a computer carb.

 

I have the LO3 TBI motor.

 

You don't want either of those, then. You'd need a distributor that will work with the computer.

 

SOB...Well here are the 2 that I am talking about.

MSD:
http://store.summitracing.com/partde...5&autoview=sku

ACCEL: This is computer controlled but only has mechanical advance

http://store.summitracing.com/partde...5&autoview=sku

 

Neither of those is what you want.

The Accel one seems a little strange to me... designed to work with factory connectors, but has centrifugal advance.

 

So I need something computer controlled with both vacuum and mechanical....but no HEI? What the hell do I buy then. Lol. I could have sworn the MSD one would have worked...SOB

 

You need something with no mechanical or vacuum advance. The computer will control the timing.

"HEI" is meaningless, it's just the name that GM has used for all their electronic ignition systems since 1975.

 

DAMN....LMAO. Thanks alot....appreciate it. Well time to start my search.

 

Just for curiosity why are you changing the distributor?Are you having problems with it?
As stated above if you want a new one,and you car still has all her computor controls,then you have to go with a computor controlled dist.The dwell and advance are handled by the module in the distributor sending signals to the ECM