123 R-V-IE Distributor vacuum question, Stock D-Jet 1.7L in '72 914-4 Options

[Stev914]

Greetings 914 Worlders:

I'm happy to be asking this question when my car is running GREAT. I'm just really trying to understand how the engine works, and I am puzzled by this.

Q. How does the 123 R-V-IE work with one vacuum line when the stock distributor has two (advance & retard)?

Longer story:

My local mechanic recently replaced my stock distributor with the 123 R-V-IE and adjusted the settings. The engine is mostly stock and has the original D-Jet. It's driving great. I note that there is a single vacuum line into the distributor (I assume this is vacuum advance). The other green hose (I'm assuming this is the retard) is fitted with a plug. Car runs great.

I have my old distributor, which has the advance and retard connections, exactly like you see in this video tour by George Hussey:

https://youtu.be/ioJ1yYU5MrM?si=sEvnLv0Z_cDd_h1s&t=220

Again, the vacuum retard hose in my car is just fitted with a plug now. I am assuming that's not a problem, but I am still wondering how the 123 R-V-IE is meant to integrate into the vacuum system. Here's a great illustration I found here on this forum posted by Jeff Bowlsby:



Sorry for the very newbie question.

Steve
1972 914-4

[worn]

I defer to others but I think that the modern dizzy can use one signal to handle both advance and retard, while the original used two different types of vacuum signals to accomplish the same function without bits and zeros and ones.