I take it that 34 degrees at 2200 Rpm is with the vacuum disconnected to the advance. That is coming on too soon for a stock cam. About 35 degrees would be about right. Check the advance springs. Check the vacuum advance chamber with a vacuum pump. It should start about 6-10 degrees & be all in at 15-16. It could have a broken spring. Try driving with the vacuum disconnected to the vacuum advance.
Does it do it cold or just when the engine gets hot? Does it sound like all the cyls. knocking or just 1 or 2?

George

Last edited by Wrenchbender Ret.; 07/09/2019 2:58 AM. Reason: Too many RPM's
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing.
1972 Chevy c10 Cheyenne Super
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