Hot Rods SBC timing question

I thought I knew the answer to this question until talking to a few of my gear head buddies last night. When setting the timing on a SBC with a timing light using the marks on the timing cover and balancer, do you unplug the vacuum advance and plug the port or do you set the timing with the vacuum advance hooked up? I always did it by unplugging the vacuum advance, but after talking last, I’m not sure. I figured you guys would know the correct way. Thanks in advance for all your help.

 

unplug the vacuum. Then after you know what the timing is, you might connect the advance and see if it changes, either at idle, or when you rev it up.

 

you unplug the vacuum advance and plug the vacuum port. You also check your total advance with it disconnected if you happen to have an advance timing light or the balancer is marked for it. When done reconnect the line and check that the vacuum advance is working.

 

After reconnecting the vacuum advance, the idle speed may need to be reduced slightly.

 

Thanks guys. Did as you described, runs much better now. Thanks again. This is a lesson I will not forget or be misled!

 

And, don't always listen to your 'buddies'.

 

Ain’t that the truth!!