No Advance Mechanism!!

[johnharrill]

...and yet it runs.

The 1967 coupe I'm working on had an aftermarket ignition system that was installed by the P.O. I could not determine the manufacturer of the magnetic trigger, so I replaced it with a Pertronix Ignitor II. Also replaced the MSD 6A. When in the distributor, I noticed all the parts of the mechanical advance mechanism had been removed.

But the car ran and drove pretty well. Now, ChatGPT tells me that neither the MSD nor the Pertronix have any provision for ignition advance. The MSD box failed, so I removed it and I'm running with just the Pertronix Ignitor II and coil.
I'm grappling with a dodgy timing light to see how much advance I'm missing.

How is this engine able to rev beyond 2000 rpm with no mechanical advance?

[Stefan2000]

Are you sure that there is no old style timing computer or programmable timing computer like the MSD 8980 or MSD 8981 hidden underneath your dash?
They were products from the 80's that eliminated the need for a mechanical advance system and were usually connected to an old MSD 6 ignition box.

[johnharrill]

Nope.

[Stefan2000]

Well, it's not unthinkable that if you set it to static timing of around 25 degrees that it will run somewhat decent. Might be a bit of a load on the engine at low revs and high load, and it might run out of steam a bit early in the higher revs....

[johnharrill]

Put a timing light on it. Definitely not advancing going on.
So, I'm going to retro fit the distributor with the advance mechanism. I see there are a couple of vendors that offer weights/spring/pins as a kit.

Any advise on which set to buy?