Question about vacuum advance timing

[AwesomeJ10]

I'm tuning the 'new' 401 in the waggy. It's currently setup with a Howell TBI without timing control. It also has a TFI coil.

I'm using a junkyard dizzy with the vacuum advance that was on it.

I have it timed at around 12 deg advance at idle. When I rev the engine the timing mark movesto about ~20 degrees.

Shouldn't the timing advance to more than 20 degrees?

[Stuka]

35-38 is what you should be at for total advance.

If you unplug the vacuum advance what is your timing at? That will let us know if your mechanical advance is working or not. If its the same, it means your vacuum advance needs to be adjusted, which is done with an Allen wrench in the vacuum advance hole. That or the linkage inside is frozen. A vacuum pump with a gage comes in handy here.


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