Firecore Mechanical Advance Distributor Setup

TroyCo

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So I received the above mentioned unit in decent condition a while back when trading for parts for my 440. Unbeknownst to me, it was a mechanical unit, not a vacuum advance unit. It's also set up to run with an MSD box as opposed to the Mopar ECU.

At this point, I'm trying to decide if it's worth using, or should I find a vacuum advance distributor? I know the vacuum units are better for MPGs, but honestly I'm not too worried about that. Aside from that, I've honestly never used one of these units before, so any advice you all have is appreciated.
 
If you are going to run the MSD distributor, you are stuck with using their control box. All of the MSD ignition stuff is expensive, the control unit with the harness will set you back somewhere around $250. The make the billet distributor in both mechanical and vacuum advance but I don't know if the mechanical unit can be converted to vacuum advance. These were mostly a high end performance setup used on some track engines but there is no reason this setup could not also work on the street. For what it will cost you to buy the MSD control unit and harness, you would probably be farther ahead to just buy the complete Mopar Blue Box setup which is more than adequate for street use.

Dave
 
I would just order a new Mopar conversion kit if your car is not set up for electronic. If your car is already set up with electronic ignition, just get a good solid vacuum advance distributor for your engine.
Plug it in set timing and go.
$60./$100. on rock auto for a new or rebuilt.
 
Watch the RA ones will it work? Definitely but the curves are set up for a spread of say B 361, 383, 400, motors so the curve will usually be wrong. You will have to recurve it.

Same with the MP kits usually a fast curve in them .
 
We have no idea what the OP wants to do with his engine. I just saying he has much cheaper options then going down the rabbit hole of aftermarket performance parts. Me. I buy original and recurve to what I need, but not many have the option.
 
I am lucky I have more than what I need doing distributors. Mopar is great set up right. I never get the 1000 ign set up unless racing and need that 1/10 of a second gain.
 
I looked back at OP other posts. I would install a stock Chrysler distributor. I see that Troyco is in Oshawa, not far from me. I can recurve it if it needs to be.
 
So I received the above mentioned unit in decent condition a while back when trading for parts for my 440. Unbeknownst to me, it was a mechanical unit, not a vacuum advance unit. It's also set up to run with an MSD box as opposed to the Mopar ECU.

At this point, I'm trying to decide if it's worth using, or should I find a vacuum advance distributor? I know the vacuum units are better for MPGs, but honestly I'm not too worried about that. Aside from that, I've honestly never used one of these units before, so any advice you all have is appreciated.
IF the MSD distributor was something you wanted to use, then get the electronics to make it work. IF it was a "happy find", unexpected, then get something else. There are several choices for a Chrysler-type electronic ignition kit, whether from Ehrenberg on eBay, Mancini, or Mopar Performance. Used to be that the MP kit's "quick" advance curve maxed at 3000rpm, which the current ones might also do. At least the above-named vendors understand what "OEM-spec" is and means to the quality of the components.

In the "auto supply brands" realm of things, new or reman/rebuild, they will usually fit everything from the first B/RB engines in 1958 all the way to 1978, which means the advance curve will be "will work" rather than being specific to what YOUR engine started life with. Yet, the basic advance requirements of the B/RB engine will be the same all the way through. What changed was compression ratios and emissions controls related to ignition timing. Not to forget that the advance curves of the 2bbl 383s seemed to be pretty much "as desired", with total usually ending at 36-38 degrees BTDC total advance, whereas the 4bbl engines usually had less total. SO, rather than being "plug and play" (which might work decently well), you'll need to verify what is in the distributor and go from there. (as to total advance and when it happens).

Vacuum advance IS necessary for good fuel economy. Once, years ago, out '66 Newport 383 2bbl suddenly dropped to about 13mpg average, from 17mpg average for the amount of freeway driving I was doing. Everything looked good, until I put the carb on fast idle and checked the ported vacuum (it was there), but the engine rpm did not change with the vac advance line hooked up or not. So a new vac advance unit was installed and all was good again. MPG came back, too!

Users usually want a mechanical advance only distributor for full race vehicles or medium-duty truck applications. Uses where manifold vacuum is usually too low for the vac advance to really make any difference in performance. Some used them on multi-purpose vehicles, too, but with the added expense of "no mpg" to deal with as there might be a bit more prestige of having it (and being able to afford such things).

It's been predicted that fuel prices will be up for another six months. Who knows what the then-current world state will be in THEN, so it might be best to plan ahead and get a vac advance distributor now. FWIW. YOUR judgment call.

Just some thoughts,
CBODY67
 
Never run without vacuum advance on the street unless you have a ignition ECU that controls all the timing, like a modern car.
Will a mechanical only work? Yes, but mileage suffers, unburned fuel wears at you cylinder walls and the temps will be higher at the exhaust valves
 
I've seen some questions about my set up, so here goes. I'm building a stockish 440, 1973 motorhome short block with low compression pistons and stock bore. It's currently at the machine shop, getting a refresh. The block will be decked .010-.020 to help with compression.

It has a set of 516 heads to boost compression, exhaust valves resized to 1.74, and a mild gasket matching. I'm also using an Edelbrock CH4B intake with a Holley 3310 carb. The cam I'm using is a Comp XE 262. Overall, it's a rather mild engine. I'm building this to be more of a torque engine that should hopefully run happily on shitty 87 octane fuel. Future plans are to add a 3/8" sending unit and lines.

The car is already set up to run the stock type electronic ignition. I've looked at both a MP distributor, or the FireCore vacuum advance unit. Both are roughly a similar cost. It seems like running this mechanical unit will be more trouble than it's worth.
 
With the not great burning characteristics of OEM BB heads you definitely want vac adv on the street
 
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