I've noticed over the years that my 73 351C runs better if I adjust the tune off of the factory settings. Idle speed up a little, timing a little more advanced. It occurs to me that since my engine was rebuilt and over-bored once in the past that the factory settings probably don't really apply anymore. The factory setting are more like guidelines.

I haven't applied this logic to the dwell setting, but am considering it. Has anyone done this?

Do the newer electronic ignitions allow adjustment of the dwell (the electronic version of dwell)?

For instance, I tend to tune based on a finely tuned calibration tool. The radio antenna. I basically adjust things like the carb balance based on the amount of antenna wobble I get. Less wbbble, smoother running.

My car had been running smooth as butter. But, recently I took it to a shop and they tuned it to the factory specs. After that, it didn't run as well. This got me thinking that the factory specs may not really apply to a rebuilt, or even an older well worn engine.

The way it runs right now, it's smooth for a few seconds, then appears to skip a beat, then is smooth again. This seems like some kind of timing thing, but the timing advance doesn't appear to affect it except to change the time between stutters a little.

Thanks,

John

 

Factory specs don't mean sqaut on a modified engine. And especially not factory specs from 40 years ago. They used different fuel back then as well.

 

no the electronic ignitions have no provisions to adjust dwell. thats why electronic is sooooo much better no adjustments to make. no setting point gap, no moving parts to wear out. i mean the pickups do fail but not that often. you get a stronger spark. you can open up plug gaps for more power too. i tune my carbs with a vacum guage, install the guage to a good manifold vacum source. then slowly turn each idle mixture screw in till vacum drops off a little then start turning the screw out till you reach the highest vacum reading repeat for the other side. and like 67 said your original tune specs mean very little anymore.

 

if it's modded tune it to run good.. factory spec is just a guideline that won't really apply in your case

 

actually the pertronix II modules adjust dwell according to rpm
I am very happy with them. If your spindle (the part where the rotor sits on) has play then you will need a new distributor.
the pertronix II flamethrower and coil is good for the money (my opinion). electronic ignition will usually give you a tad better gas mileage as wel..

and as to your question forget about factory settings when the car is running better on another setting.
a garage that are not used to old Fords might opt for that just to be safe.
listen to what 67mustang302 says. he has experience

 

The antenna calibration is priceless. You must have learned that from an old timer

The best way to adjust your air mixture and carb is with a wide band 02 kit. These are not for computerized cars anymore. You can precisely adjust your air/fuel mixture and find the correct power valve and jets for your carbureted vehicle. I plan on buying one for my new 349 stroker. I have way too much money into this project to run her lean. Here is a link to just one brand. There are half a dozen brands out there to choose from,

http://www.accel-dfi.com/ProductDeta...minselection=0
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I couldn't agree more with the above statement.

I must strongly disagree. I don't know how that myth got started. Points eliminators are just that. Points eliminators.
Pertronix 1 and similer devices are simply electronic switches intended to replace mechanical switches.
The only reliable way to get a stronger spark to allow for wider plug gap is with CDI ignition box and/or a hotter coil.
I said reliable because, in theory, you could get a hotter spark by upping the coil primary voltage, but you will toast a stock coil over time.

 

aye. if you have a high voltage coil, then you can run a 1mm gap ... or whatever that is over in the states;-)
buty that's mostly for fuel efficiency (gas/mileage) then power
the pertronix I replaces the points and the pertronix II adds rpm-adjusted dwell to the scenario