Originally Posted by Ironcross

My debates have all been on the race track, with the "Walts Puffers"...National Champions record holding drag cars.....All gapped at .035...

Emission engines with converters, air pumps, wide gaps, high tempertures. ect. ect {up to .080} were the product of the governments attempts at controlling so called dirty cars...One big reason the 1970 Vetters never got the LS-7 engines and as a result HP started to drop all across the board no matter what brand of autos.....Hell, Vettes even were sold with 305 engines and no 4 speeds....

But if you have one of those no power Vettes gap them wherever you like...I guess it don't matter....But the HP years of the late 50`s and 60`s all used .035 didn`t they........

Originally Posted by TCracingCA

i index my plugs, I side gap but shape the tips with the MSD hot stuff on fully worked chambers etc. minimum squelch or howlever u spel it, and custom relatively flat top pistons riding on long rods.

PS I only posted to give MikeM something to do for the next 5 or 6 posts (giving him enough to work with)!:cheer s:

Originally Posted by Mike Ward

Your VH box is full too.....................

Originally Posted by Viet Nam Vett

And he Never called anyway.....

Originally Posted by MikeM

I forgot. I have your number stored in my phone. John gave it to me. When I get ready to hook it up, your phone will ring! Got a question on TV's too!

Originally Posted by 65tripleblack

If "Ollie" chimes in he's gonna tell you that if Chevy designed it that way in 1955, then there's no reason to change it because the state of the art has not advanced beyond what it was 60 years ago.

I used to index plugs. Difference, if any, is so small that it wasn't worth the effort.

Squelch is for walkie talkies. Quench is for engines.

Originally Posted by Westlotorn

High end racers all index the plugs so the spark plug gaps face the intake charge.
It makes a difference but takes time so other than high end racers nobody does it.
The amount of difference made is very small but free horse power is always hard to find.
I would bet on a 450HP engine indexing is good for no more than 1-5 HP but it is totally free and available to anybody willing to index. As far as gaps go If running standard OEM ignition run the factory recommended gap. If you have converted to an HEI or other super high voltage system you can run .045 and get some advantage mostly at idle. GM did play around with gaps up to .080 but came back down to .045 over the years. GM also reduced voltage over the years, they were as high as 50-60,000 volts in the 1990's but now are around 20,000 volts with current Coil on Plug technology firing Iridium plugs. Iridium plugs fire well with lower voltage than the Platinum plugs they replaced. Modern engines using OBD2 detect misfires at idle and the wider gaps, .060 and .080 had too many misfires detected at idle and caused issues for GM.
I was late to join this party, I need to Thank you guys for the entertaining posts.

Originally Posted by TCracingCA

Probably just makes me think in my own mind that I am on the cutting edge!

Originally Posted by MikeM

Yes, the mind is a terrible thing to lose. While yer tinkerin' around with that plug all day long, I'm out ridin'!

Originally Posted by 65tripleblack

"Spark plug gaps were increased in the 1970's to better fire the leaner fuel mixtures. The wider gaps also meant higher powered spark and that's why you got HEI."

Both of these statements are true if "higher powered spark" means "hotter and larger" spark kernel. Not only will a hotter and larger spark ignite a harder to ignite lean mixture, but it will also ignite an exhaust gas diluted mixture, an overly rich mixture, and an oil contaminated mixture. More consistent firing (no "misfiring") not only makes the engine idle smoother, run smoother, get better fuel economy, and produce more power, but it also keeps the spark plugs cleaner.

"When the point gap closes, it give the coil more time to built a hotter spark so it seems one would/could cancel the other and you'l get no misfire."

This is partially true. A non HEI coil as used on Chevys from the 1960s is capable of producing about 18 kV, although only about 12 kV of that is needed to cause a spark to jump a .035" gap in an atmosphere which is not exceptionally dense...........the residual capability of the coil is used to overcome losses in the secondary wiring due to breaks/high resistance. If a cylinder is running a denser mixture, that plug is gapped wide due to wear and the wire feeding that plug has high resistance, then the coil will supply enough voltage over the nominal 12 kV to create a spark.............up to its design limit of about 18 kV. "Hotter" 40-50 kV coils will produce whatever voltage is necessary to cause a spark to jump a wider gap with residual voltage to overcome bad wires with breaks/high resistance wide gapped plugs as well as major variations in mixture density and leanness/richness..........................up to the design voltage of 40-50 kV.

Originally Posted by 69427

Remember, that 40-50kV rating is just the coil's insulation/dielectric rating. It has nothing to do with what the actual voltage and energy levels are that come out of that coil.

Originally Posted by Kerrmudgeon

Old guys always remember stuff differently it seems, even the same stuff.


We travelled across the US when i was a kid, towing a house trailer as well some times, through places like death valley. i don't recall ever being in a maintained car that overheated.
I bought a canvas route 66 spare water bag as a kid and never used it. hung on my garage wall for years.

Originally Posted by 65tripleblack

Explain. Make it simple because I'm not an electronics genius. The way I heard it explained is that a coil with a higher rating is capable of stepping up the voltage to a higher level than a standard coil. I think that a standard coil such as used back in the days before HEI was capable of about 18 kV maximum. Regarding these 40-50kV claims, picture an analogy: your shop air compressor. One manufacturer's ad says their model is a 250 psi unit, while another manufacturer says theirs is 500 psi. Which one is better? The 500 psi unit sure sounds better, until you find out that the big numbers only describe the tank pressure capability (burst resistance), not the pump capability, which might only be 125 psi tops. Also, those tank pressure capability numbers tell you nothing about the air CFM capability of the unit. To use air tools you need both line air pressure and air flow (CFM).
Impressive advertising numbers (250, 500) such as these examples don't give you any real world information to tell you if they will work better than (or even as well as) the humble dust and grease covered compressor hooked up in the corner of your shop. Ignition coils are kinda similar. It's what they put out time after time that counts, not what their blow up point is.
As far as ACTUAL voltage produced, that is more or less adaptive, meaning that any coil will produce only as much voltage as needed to overcome the resistance in the secondary circuit plus whatever is needed for a spark to jump the gap, Correct up to its rated maximum. Granted, a 45 or 50 kV coil rarely, if ever actually produces 50 kV. They do produce more than that produced by the standard coils of the fifties and sixties. Not necessarily. If you gap your plugs at .045", the old coils wouldn't have enough voltage potential to enable a spark to jump such a wide gap. You can't necessarily blame the coil. It can also be caused by the points/condenser. The potential voltage output of a coil is greatly affected by how fast you break the primary current, and mechanical points aren't terribly impressive in that function. Wide gaps force the coil to produce more voltage, thus a hotter spark, larger spark kernel, which causes a more complete burn as well as cleaner plugs.

Back in the old days, guys used to "short gap" the plugs to compensate for misfiring due to a problem in the ignition system.

Originally Posted by AZDoug

Who's the latest avatar babe? She looks familiar.

Doug