FAST, now a part of Comp Cams, also owns Crane, so, those FAST oil filled coils are Crane specification.

EVERYONE knows I am no fan of PerTronix ignitions, except when used like they should be, .032 plug gap, good oil filled coil, ballast resistor in place, good set of mag suppression, spiral core wires, and only the first Ignitor. Makes for an acceptable electronic set of points, nothing more. OIL FILLED PerTronix round coils, perfectly acceptable, will work just fine with, and without a ballast resistor, low perf, HEI and even CD ignitions.

That said, PerTronix has two different versions of their round coils, epoxy filled, not worth a diddly darned, and the perfectly acceptable oil filled, this one is good stuff. I seem to remember that the PerTronix coils have writing on their boxes that says "40,000 VOLTS". What I also remember of that was, in parenthesis and extremely small print, (AVAILABLE). This does not mean a coil will instantly make any ignition system make 40K volts. MSD CD ignitions do, but they are a capacitor discharge setup, they charge a capacitor, then force the volts into the cold coil. EVERYTHING not CD, has to rely on coil saturation, or, "dwell". An HEI has a dwell extender built into it, that is how it makes higher plug voltages. Other ignition systems today falsely referred to blindly as "HEI"...DON'T HAVE THOSE DWELL EXTENDER DRIVERS, they are simply an electronic points replacement system, nothing more, no matter the input volts, coil, plug gap, etc, etc.

Essentially my experience....don't care about 1/4 mile racing so the ET aspects of all this are unimportant to me. I have mentioned that the car starts better and idles better with the old MSD in other posts like this one. My ancient, pre digital, 6Al has never missed a beat. Same for the coil and the billet small cap MSD distrib. Even if I wanted a large cap HEI I have to run the small cap distrib. because my 67 Vette 3x2 is a little short on space to accommodate the HEI. Took the MSD parts out of the boxes to install them and never looked back other than fooling with the curve.

I sure understand the MSD haters who are angry about being stranded on the road and I also understand the frustration of the folks who laid down cash looking for additional 1/4 mile performance they did not get with the MSD. I once had a 67 Ram Air GTO with the factory electronic ignition and I drove if forever with no issues. Plugs lasted well and it always started quickly and maintained a smooth cold start up idle even when the air temp was in the teens, same as my LS6 454 does with the "vintage" MSD parts!

How does one limit timing w/HEI ?

Bought my MSD 6AL used in 2005. Since then, haven’t had any problems with it to date.

Herein lies the real issue.

On one hand I can't fault China for building what the "investor groups" specify they want. Cheap component parts to further cheapen down the overall quality of the product are fine as far as the investors are concerned. The investors are long gone from ownership positions by the time the name of the product is in the dirt.

China can make junk well enough on their own and when you add their ability to mess up by themselves to cheapened down specifications submitted by their "investor group" masters you have a toxic brew to be sure. Add in the good old US government trying to save the world by "discouraging" things like oil filled coils in favor of epoxy filled coils that don't get the job done then stir gently and you have completed the recipe for disaster (AKA roadside breakdowns).

One of the first upgrades to my first car, a 68 El Camino, was an HEI. Now this was in 78, so the parts
were still worth having. Never wanted the MSD because I'm no racer. Years of trolling the jeep forums
leaves me with the impression these boxes only last two years. Nothing cost efficient about that.
Always kept an extra HEI module in the glove box after the first tow home in the rain. HEI suffers the
same problem of outsourced production, with modules being bad right out of the box a common occurrence.
So... is there a source for USA-made HEI modules?

"How does one limit timing w/HEI ?"

Now, that has started full on wars from people not knowing, nor caring about how the curves were designed in the first place. Jamming a screw in, ripping, tearing, grenade attack, full on nuclear detonation, welding/brazing, hacking, hammering, dynamiting, are not the right way to set the mechanical curve on a large coil in cap HEI. We designed these distributors to use a myriad of combinations of center curvatures, and weight profiles, to set the start and limit points,and degrees of curve, with just at 437 different combo's of weights/center. Getting the right curve for yur application, doing it the right way, may well take decades of test, change, test, change. And, the after market "Curve Kits" are NOT the answer for a street driven mechanical curve, because those curve kit weight and center combos are not designed for street use, they are for drag racing only. Those kits make it workable to run 18 to 20 degrees initial, no vacuum advance, and give 14 to 16 degrees of mechanical advance, for drag racing.

The ONLY real "performance" curve ever used in a large cap HEI from GM came, comes in carbureted engine ZZ series crate engines. 41 weights, 375 center. This combo is also used on late 70's/early 80's 350/454 Suburban, and truck engines.

As far as the vacuum advances, more "top tuners", "Dyno Hero's", and really bad "techs" usually have NO CLUE as to how to set one up right, so, they tell us to leave it disconnected, for various bogus reasons. A properly set up vacuum advance, even a stock one, can really help an engine cool better, drive better, get better fuel mileage, and just plain help with carburetion and performance. There is one topic on a Pontiac board that has a person fighting poor performance and heating issues on is stock 389, and he takes it bck to the mechanic, whom insists the vacuum advance won't help anything. Once the car oener did the actuel vacuum advance mods to set the degrees delivered, and plugged it into the base of the carb, the engine cooled right off, and woke right up.

He now doesn't take his car back to that "mechanic", it runs too well now for him to let it slide back into problems from the top tuner mechanic he had. Some other really great people try to help as well, nice folks, but they too have been indoctrinated to not use the vacuum advance, let alone correctly. Not bad people, they just never got the right info to try and prove to themselves works.

There are people out there that have listened to a few very knowledgeable people, done it right, and saw the fixes that work. Just have to hit on the right person.

Curving a large HEI, not too tricky, but, the right weight and center combo, along with the right adjustable vacuum advance kit, and the whole mess can turn into a right nicely curved ignition.

Thanks ! I have three of those bushings. I checked the resistance and one is at 5K ohm !, the other at 25 ohm, and the last one at 1.8 ohm. I put the 1.8 ohm low resistance bushing in and I bought a new coil in cap coil. I have three of those coil in cap now. One made in USA, very old, but, still works, no date. One with a 2011 date that I had installed in my car, and the new one I bought this week which was made in Feb. 2019. I put the new one in and I am keeping the other two as spares. In the future, I will consider getting rid of the coil in cap. Thanks again for the tips !

Hahaha, amen on the Pontiac story ! Hint, above info works on Chevys too.

Called engine builder on a pathetic running SB. Word back, “Get rid of the HEI”.

Swapped to RTR MSD. Cured many problems, very easy to fine tune. Bought 2 more for other cars.
Going to MSD was the most significant and cost effective change I made.

My Chevys are not all out drag cars, but I do expect very spirited performance. After all, they re Chevy powered 💪

Can you get 25 degrees initial, Max 37 with HEI ?

Oh, and of course
all my cars have vacuum
advance on bottom
of carb

"Can you get 25 degrees initial, Max 37 with HEI ?"

Yes, with one of those aftermarket "curve" kits I described above, but....WHY? And, with the proper emissions weights/center pairing, with stock parts as well. Once again, WHY?

This is “WHY”.

Here’s more good info, just search ebay for him. Also another vendor I buy from, super guy. I’ll try and find contact info.
FBO Ignition Products Now Shipping to Canada Australia and most European destinations USPS 1st Class Mail $7.00
The Black bushing supplied by MSD with your distributor will allow 18* mechanical advance, most American V-8 engines require a total of 34-36* under load so with the largest bushing they make you can only get 16-18* of Initial timing which in most performance engines is not enough to achieve a lean clean and crisp idle and get rid of that eye watering Raw fuel fumes caused by inadequate initial timing.
Incorrect timing can also be responsible for not only a rich idle but overheating in traffic, stumble off idle, lazy throttle response, lost HP, burned out header gaskets, discoloration of ceramic coatings and poor fuel economy. Without enough Initial timing it is impossible to set up the carburetor correctly as it won't respond to adjustments without enough timing to burn the fuel If your Drag Racing you know that consistency is #1 in Bracket Racing, you will never be consistent with the combustion chamber loading up with fuel and fowling plugs. You want to win?... Get the timing right!
This Bushing kit will solve many of these issues if the distributor is correct for the application. Our rule of thumb is "If the engine will make 10" of Manifold Vacuum at idle with the idle timing set at 30* then it should have a Vacuum Can type Properly curved distributor and connected to a CONSTANT Manifold vacuum port. These bushings will fix most rich idle conditions, 80% or more of the rich idle complaints we get are NOT the Carburetors, If your not sure just call our tech-line and discuss your issues with an Ignition/Carburetion expert with over 45 years experience. We have Email and of course Phone and Text access for tech help. Now only $7.00 Shipping to Canada, Australia and most of Europe
PLEASE NO Calls regarding Edelbrock Carburetors

Interpretations:

"CONSTANT" is FULL manifold vacuum
30 initial degrees idle timing would not need a vacuum advance. But, with 18 degrees INITIAL, AND 12 vacuum advance degrees, on FULL manifold vacuum, sourced from "the bottom of the carb"...would.

"If your not sure just call our tech-line and discuss your issues with an Ignition/Carburetion expert with over 45 years experience" Well, I have that much experience, with both ignition systems, and working for Holley on Pro-Stock and other carbs, and, was one of the people working for Chevrolet Skunk Works and Duntov that was involved in the design of the large cap HEI, and worked on its predecessors, both the T.I., and UNITIZED ignitions. Nobody needs to call me, I will answer questions right here, just ask 'em.

But, with 18 degrees INITIAL, AND 12 vacuum advance degrees, on FULL manifold vacuum, sourced from "the bottom of the carb"...would.


And as soon as gas is mashed, vacuum falls, timing drops to 18, your car stumbles and I’m gone


For “hot” street Chevys, time for 36, 25 idle. Then hook up vacuum to constant vacuum. This will put it close.

Gets rid of gassey smell, poor off idle stumble, weak idle hp etc.

The initial timing on my mild 454 is 12 degrees, 19 mechanical, and 20 vacuum advance, hooked up to manifold vacuum at the bottom of the carb. At ~750 rpm idle the timing is 31-32 degrees. Runs cool, idles well. When I mash the gas and that extra vacuum advance timing drops out... the car either takes off like a rocket or burns the tires, depending on how far and fast I mash. No bog, no stumble, no hesitation. Excellent idle, acceleration, and cruise manners.