setting timing in 68 c-10 with 250

[dwmurry2006]

Alright she is in time. Did the paper towel inthe spark plug hole trick. Did it 5 times to be safe. Checked out everytime. Rotor at number one and timing mark at 0* everytime. So i' still confused how is it so that I'm at tdc and 0* but with it idling smooth my mark is at the 12o'clock position.

My other question is do all hei distributor use a hall effecct for the vacuum adv. Cuz on my points dist. It moved the points plate. Cuz I still have the issue with not being able to use vac adv. It advances properly watching with timing light it just starts cutting out and bucking and jerking and ending with a big backfire out exhaust. I'm at my wits end i need to get this fixed. Its my daily driver.