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I know the inline pages, but since not registered I have to ask here. I am one of about half a dozen guys responsible for maintaining our sweepstakes prize 66HT with 200 and automagic.

Factory settings: 12 degree. The engine shaked badly off idle, we raised the initial advance to 25 where it pinged a little, then backed off slightly to 23. No shakes, no pinging. The manual says that mgp and performance might improve with extra 5 degrees over 12.

The head has been milled because of warping, so compression has increased. It either shakes or pings with 87 or 91 (US measurement) oct but gives a few degrees of freedom with 93.

It had distributor with both centrifugal and vacuum advance. The vacuum didn't advance much. Now it has vacuum only advance distributor. Should the vacuum advance conncetion be in the intake manifold vacuum or in the ported vacuum?
 

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If the harmonic damper has not been replaced, it may have slipped, giving you a false reading. I would ignore the timing marks and use a vacuum gauge and tach to set for highest vacuum/rpm at idle.

Vacuum to distributor should be ported; little or no vacuum at idle, increased vacuum with engine rpm...

Also, make sure you have the firing order correct.
 

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Hi Art you need to find TDC and see where your timing marks are. You need a piston stop that screws into # 1 spark plug hole,Turn the motor over by hand until it hits the stop,put a mark on the balancer,turn the motor the opposite direction until it stops mark the balancer.half way between the two marks will be tdc,see if this mark matches the factory mark (I doubt it) Robert
 

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The vacuum should be connected to the carb. What carb do you have? I would not go by the damper, the timing marks are usually off. Just use the ping method you mentioned. You can check my Inline Performance page for some tuning info. Click the sig. below.

I also noticed you said compression has been raised. By how much? You want to stay in the 9 range or else you will get pining or detonation as you stated. You might have to get a new head if your compression is too high or maybe water injection.
 
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