I'm ready to reassemble my 455. I've donut that the 71 Chassis manual shows timing marks on cam and c/s gear both at 12 o'clock position, while the period Chilton and instructions with the timing set show cam mark at 6 o'clock and c/s gear mark at 12 o'clock. Which is correct?

 

the chasis manual is correct chiltons is incorrect for oldsmoblie

 

You've donut?

Me want donut.

Actually, neither is wrong.
Crank at 12 / Cam at 6 (like a Chebby) will get you TDC ignition on #6 cylinder.
Crank at 12 / Cam at 12 will get you TDC ignition on #1 cylinder.

- Eric

 

They are both correct.

Once again, it doesn't matter. The crank rotates twice for every one turn of the cam. Line them both up at 12:00 - 12:00. Now turn the crank one turn and they will be 12:00 - 6:00. All that matters is that in one orientation the #1 cylinder is at TDC on compression and in the other orientation the #1 cylinder is at TDC on exhaust.

 

Which means that you either stab the distributor pointing to #6 or #1 depending on which mark you use.

 

Thanks for the information. Should be able to make it work now. The "donut" started out as "noticed" until spell check got ahold of it! Thanks again.