I have a Pertronix unit in my distributors and is there much to be gained (noticable gain) by installing a higher voltage ouput coil?

 

There's a lot of hype regarding coils...output, hotter spark, etc. A coil will put out a spark when needed and that's about it. The better coils have better saturation time and can respond better and faster, but the stock GM coil is fine for most all purposes.

The difference is when parts start to wear such as spark plugs...their gap opens up or the electrode corrodes away. The coil will produce whatever spark energy is required to jump that gap...up to the capabilities of the coil. That's where a high performance coil can show its stuff...it will keep producing enough spark to jump that gap past where stock coils can. If it takes 35k volts to fire the plug, a 40k or 45k or higher volt coil will only generate 35k volts since that's all that's required. If there's enough wear that it takes 45k volts to fire across the plug gap, the 40k volt coil can't do it, but a 45k or higher volt unit will.

If you keep your car properly tuned and maintained, the stock coil is all you need.

If you're looking for better performance...instead of replacing the coil (assuming the coil is not defective), try different advance weights and springs in the distributor. You should notice some improvement in acceleration and power.

 

your not going to get 34 mpg because you bolted in a Hi Performance ignition. It may start a bit better, might get a tad more mpg, might do better on lower quality gas. Is it better than stock? Marginally.
Is it worth the price? Depends on how muh extra cash ya got. My choice is mostly stock ignition, hot coil, thats about it.
New wires, cap and rotor now and then

 

Brother Roughrider, you nailed it with a sledgehammer that time!

As to schspitzen-schsparken, I was experimenting in my misspent youth & ended up taking the "parts start to wear" concept, turning it upside down and using it to my advantage.

Here's something to play with:

Get everything "perfect" -- set your timing, fuel mixture, everything to work the best you can -- then pull your plugs back out and open their gaps on purpose to the widest setting your coil(s) can handle. How can you tell? Any coil's saturation (calm down, no physics lecture today!) will catch up to idle speed & spark over a fairly large gap. Grab a plug wire if you don't believe me! The problem comes at the other end of the RPM scale. At redline, assuming a too-wide sparkplug gap, the coil won't have time to reload itself when the next contact closure is made & therefore a misfire will occur. That's the "Bronx Cheer" you hear in the middle of your beloved Valkyrie's song. That's nature's way of telling you to tighten up (your plug gaps)!

So what is that "too-wide" gap? I dunno. You have to measure that yourself, because it all depends on your coil, your plugs, your plug wires, the connectors crimped onto them, the boots, the weather, the tea leaves in your cup, phase-of-the-moon, whatever. Go measure it for yourself and then you'll know.

The point of all this is, manufacturers want the teeming hordes to use their products without complaint, so the "factory specs" are designed for that "lowest common denominator". No offense to "Joe Sixpack", but I don't mind keeping my loud toys in perfect tune, so my specs are a little different.

So what happens when the spark plug fires? The flame front starts propagating across the face of the piston, which will ultimately (within 10% of a turn) cause (hopefully) the entire charge of gas & air to convert itself to heat, pressure and stinky old exhaust gas. The time it takes for the engine to rotate that ~36 degrees is all the time you have to get every last molecule converted. If you could achieve this, you wouldn't need that stupid cat! If you start with a smaller spark, it simply takes longer. (Like you've got a lot of time for anything at redline!!) Start with a bigger spark, relatively speaking, and that flame front starts out bigger, which reduces the amount of time required to fully convert the fuel-air charge into power. That's what I think, anyway.

So my "trick" is to get everything perfect, then open up my plug gaps in steps, measuring after each change with a redline runup or three. If it misfires at high RPMs, I know I've gone too far & put the gaps back tighter a little. Will I tell you what that number is?? Of course not! I don't even know myself until I've finished, and then I jot down the number for the next time. If you must have a number, take the factory plug gap & add ~25% to ~50% of it back into itself. If the factory gap is "32", call it "30" and add 15, giving you 45. If it's "40", try "50". (that's .050" in SAE terms -- apologies to all you metric guys) The point is for you to find your number, not mine.

You're going to give up the luxury of putting off tuneups until it's convenient, because as soon as the plugs wear a little, you'll have the old "Bronx Cheer" again, but your exhaust will smell much nicer and you'll get the best possible performance from all the parts you've carefully assembled in the meantime. It's not called "the bleeding edge" for nothing, y'all!

NOW you can add a "fatter" coil!!! This will let you open that gap up even more, which will leave you looking for a fatter coils still, which will get you a place on Accel company's Christmas card list if you keep it up!

The bottom line: Running the widest plug gap at which your coil can deliver adequate sparks at redline will get the biggest "bang for your buck", at the expense of more-frequent tune-ups.

Or not, if your experience proves otherwise.

Jimgo...

 

could not have said it better my self i run gm duel point with a msd coil i love the old school even though i work on new diesel an gass every day its nice to play with points gives me that warm feeling all over

 

hallelujah LeapinLizard !