Messages

I also think about to convert to points so if someone knows reliable dual points just let us know.

Thanks for the clarification, Roy and Bob! You're right—I got my wires crossed regarding the voltage.

Voltage (12V) is fine: As you pointed out, the stock '67/'68 tach is wired in series before the resistor wire. This means it has always seen 12V from the ignition switch. The voltage itself isn't what kills it.

The Real Killer (Amperage): The danger comes from current flow. Since the tach is in series, every bit of power going to the coil must pass through the tach's internal transformer/windings.
The "Frying" Scenario: If someone installs a high-performance coil with very low primary resistance and bypasses the pink resistor wire to get a "hotter" spark, the amperage jumping through the tach skyrockets. That's what melts the internals.

The Proper Setup (The Roy Simkins Method):
By running a separate 12V line to the PerTronix unit from a source before the tach (or at the ignition switch), the PerTronix gets the clean 12V signal it needs to "trigger," but the heavy lifting (the coil power) still follows the original path. This keeps the load on the tach within factory specs.

The MSD Confusion:
I mentioned the MSD Tach Adapter because MSD ignition boxes (like the 6AL) use a capacitive discharge system that sends 400V+ to the coil. If you hooked a stock Ford tach to that line, it would be gone in a microsecond. But for a simple PerTronix swap, following Roy's wiring keeps everything safe without an adapter.

To clarify further, even with Roy's wiring, there is a hidden danger when upgrading to a PerTronix III with a low-resistance coil (like the Flame-Thrower III).
The PerTronix III system is designed for very low primary resistance (around 0.32 Ohms). Because the '67/'68 tach is wired in series, the massive increase in amperage required by that high-output coil still has to pass through the delicate internal windings of the tach.
Even if the PerTronix module itself is getting a separate 12V feed, the main 'load' for the coil is still pulling through the tach. If you run a high-output coil, you are pushing much more current through those 55-year-old internals than Ford ever intended. To be 100% safe with a PerTronix III, using a relay (as Roy suggested) is the best way to trigger the coil without melting the tach's transformer.

Horsepower: Switching to PerTronix 1 or 3 on a street engine won't give you a massive HP boost (maybe 1–2 HP). Peak power remains similar if points were well-adjusted.

Driveability: This is where the win is. PerTronix III offers Multi-Spark at low RPM for a smoother idle, better cold starts, and cleaner combustion.

The Dual Points: Dual Points were designed to prevent "point bounce" at high RPM (5,000+). However, modern replacement points often lack the heavy-duty spring tension of original racing parts.

Reliability: Points wear down and the timing drifts. PerTronix offers rock-solid timing that never changes and includes a built-in Rev-Limiter (on the III), which is an engine-saver if you ever miss a shift.

Conclusion: You don't switch to PerTronix for "racing power" alone; you do it for reliability, a smoother idle, and to stop the maintenance headache—all while keeping your original tach safe via a relay.

How do you guys keep your tach safe? The Tach is running between the ignition and if you have 12v in this you will fry it. I run a MSD Tach Adapter to keep it safe.

Do you maybe have some pictures of the Boss?

RIP Dave, I have all the books from him so his legacy will never be lost.

Godsped Doug, I will miss our conversations.

Which Broker did they used, its hard to find good shippers.

Just by the way I would need an H Servo if someone has one for sale. Thanks.

Which one? The typical H servo which is relatively still common with the smaller piston or the anomalous H servo being discussed here with the larger diameter piston like the R servo?

I would like to have the "normal" one for the 67 Shelby GT500 the other one wouldn't fit I think in a 67 C6 Tranny without machining the housing.

Just by the way I would need an H Servo if someone has one for sale. Thanks.

Still searching for a 1967 A Scratch March-May Block if someone has.

This awesome looking steering wheel is still for sale if someone is interested I can take it with me at the beginning of February 2026 and send it from the US or maybe we also can meet.

If someone wants some of the books I still have some and can take them with me at the beginning of February 2026 and ship them from the USA

I will be able to take these with me at the beginning of February 2026 if someone wants them I would be negotiable with the price if there is someone who want them. Thank you.

some more pictures

here are some pictures I will be able to take them with me in February if someone wants them