I have an MSD 6A in a 1975 Buick Lesabre w/a big block 455. It's a pretty heavy car. Would it benefit from adding a vacuum advance to it? Do they manufacture one compatible with the 6A? If not, is it worth switching to an ignition that is compatible w/ a vacuum advance? Any advice is greatly appreciated.
I'm running the MSD 6A w/o vacuum advance. A guy that re-built my tranny said a car this heavy would benefit from adding a vacuum advance. I just had a Kenne Bell 455 w/a Wildcat single plenum intake dropped in it a couple of months ago I found on Craigslist. I had a mechanic rebuild it with a cam just a little bigger than the stock one. She runs great! Alot more torque-y than my old motor that blew. Ya think the vacuum advance sould help in my case?
yes! And a Crane adjustable vac advance & recurve kit. Run your vac advance on Manifold vac if you do get it.
Smartin, thanks for your responses and recommendation. However, I'm a newbie to all of this and am unfamiliar with some of the terms. Is Crane a manufacturer? Is Manifold vac a setting on a Crane model? Recurve it? Sorry for the ignorance but your knowledgable advice is greatly appreciated.
The vacuum advance cannister is part of the distributor, and functions with the mechanical advance in the distributor. It is independent of your MSD ignition. Advance settings are in your distributor, so the question is, what kind of distributor do you have? Crane is a manufacturer of ignition components. They make an adjustable vacuum advance cannister, that can replace the stock cannister, but again, we need to know which distibutor you have, HEI(big cap with integral coil), or points distributor. Vacuum advance can be run off ported vacuum, or full manifold vacuum. You have fittings for both on your carburetor, just a matter of running the vacuum hose to the right fitting(full manifold vacuum)
My mechanic tells me he installed a magnetic pickup distributor w/the MSD 6A. Is it better to use a distributor that is compatible w/vacuum advance or is this one compatible w/vacuum advance? What is the benefit of vacuum advance? Is the magnetic pickup distributor better than an HEI or points that is compatible with a vacuum advance? Thanks for helping out the hopelessly uninformed. Any info/help is greatly appreciated.
A magnetic pick up distributor is the way to go. I guess since your mechanic suggested vacuum advance would benefit you, your current distributor doesn't have one. It may or may not be possible to add vacuum advance to your current distributor. I know the MSD Pro billet distributor does not have one, and there is no way to add one on that distributor. There are other types of magnetic pickup distributors. Find out whose make yours is. Your mechanic should be able to tell you this. Vacuum advance uses engine vacuum to advance the timing above the mechanical timing, when the engine is at light load(cruising at highway speeds) It gives better gas mileage, and better throttle response. When you accelerate hard, engine vacuum drops towards 0, and the vacuum advance falls off, so the engine doesn't ping. This picture of a stock distributor shows the vacuum advance cannister(silver) on the side of the distributor. Does your distributor look like this one?
