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It appears that the harmonic balancer or rubber mounted pulley has shifted. The large and deep groove, which I believe is the timing mark, appears to be approx 30 degrees after TDC with the timing light.
The vehicle seems to run o.k., it's just that the distributor has a large range of rotation before any noticeable stumble. Not quite sure just where my appropriate timing is or how I can determine it. Tried the vacuum style timing with same results, to big of a timing band variable. Suggestions?

 

[philippe]

I am not sure how the pulley assembly could have shifted as it and the two pulleys and damper are keyed and bolted onto the end of the crank.
I believe the large groove ends up about 'half past two' with the engin at TDC.
I am currently setting up the timing on my 3.5 EFI and can swing the distributor pretty much from one end of the range to the other and it still runs. Are you sure that after a good clean you cannot see the timing marks on the damper. I unbolt the fan and clutch to get a better look?

 

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Mark is half past two!

Phillipe, Thanks for the info. That is where the mark is approx. dwelling. I don't see a timing mark however to line this notch up at the 6 deg btc though. Is there a fixed mark I am missing on the motor cowling somewhere?

Thanks Mike

 

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Marks, Wallah!!

Wow, do I feel a little dunced! I measured the radius of the crank pully, divided by 360 then multiplied by 6 to get the dimesion of six degrees before TDC. Laid it out on the crank pully, and heh, there was something there already!! Buffed off the rust layer and, wallah, there was the timing marks with "before" and "after" stamped upon the crank pully at the timing marks. Got that one settled!! Thanks for the help.