To Vacuum Advance or Not to Vacuum Advance

AJ/FormS said

Here's another thought;
Say you had timing all in by 2800, and V-can hooked to full-time vacuum. What happens when you slam the throttle shut at some higher than all-in rpm, and the car now drives the engine with it's closed throttle,(compression braking) and the timing is say55 or more degrees?
Meh, maybe nothing.
I didn't want to find out, so I'm on the spark-port.

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AJ I like your insight.
My iron head 340 roller engine is all in 36* at 2500rpm the vacuum advance adds 10* for a total of 46* at cruz speed. I have tried to add more but am limited by 10 inches of vacuum and the advance adjustment is maxed out. Connected to full manifold vacuum.
I have made numerous 6000rpm+ pulls on the road with no issues. I dont know what it would do at 50*+, lets not find out.
Keep up the good posts