Ok so I've read haynes chilton FSM and the forums but it seems I am miss understanding something.

I disconnect vacum advance. Fire up my car and have my assistant (wife) run it at 4K rpm. I then hook a timing light to L1 and set timing by turn the distributer cap.
Then I hook up to T1 and try to set the trailing by adjusting the vaccum pod closest to the rear of the car. I cannot get the trailing set. It just seems to jump around randomly.

So should I reconnect the vaccum line to set trailing or leave it off. Or am I missing something obvious?

 

When setting the timing according to the book, you should be at idle (850). You are combining two different methods for setting the timing. Try it again at idle and you should be alright...

 

If for some reason Kents directions dont fix your issue.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/leading-timing-mark-jumps-around-why-762149/

Good Luck.

 

jumping around is not good, what kind of shape are your cap rotor and wires in?

stock has you setting timing at idle.