Ok, I have never see this, maybe you have.

Top cap is a 2444 690. That was the improved version of the first wide-contact distributor cap, a black one named 2098 765. The tan material, introduced in the '64-'65 timeframe, has higher dielectric strength (greater flashover resistance) than the previous black material. The wide-contact cap was used with rotor 2098 770, which had a necked-down, narrower end contact. These parts were first used as part of a service package 2448 273 (which also included a new coil-to-cap wire) to address cold/wet starting issues. Those three parts were incorporated into new-car production. Read all about it:

2448273.jpg

These wide-contact caps and narrow-long-contact rotors were cancelled for '66, and the Slant-6 reverted to the regular narrow-contact cap and the same 1838 516 shorter/wider-contact rotor used prior. The bottom cap is a 2642 986, which was the '66 cap (the pre-wide-contact cap was a black one, 1889 424).

I like the wide-contact/narrow-rotor setup, but I've never seen such a cap with contacts made of anything but aluminum. The benefits can be duplicated by benchtop cleverness with rotors as described in this long (but worthwhile) thread.

Rick, do you see timing scatter?
That was the first thing I thought about

The benefits can be duplicated by benchtop cleverness with rotors as described in this long (but worthwhile) thread.

Rick, do you see timing scatter?

Remember, the exact instant of spark is determined by the instant of points opening (and coil magnetic field collapse), not by the distributor rotor and cap.

The points determine timing. The rotor and cap just point the spark energy in the correct general direction.

– Eric

And back in the day, ACCEL would sells those tan caps as special high performance parts at 3 times the cost of the regular heavy duty part that they actually were.