Frank,
Just an added note from Pre '68 Dave's comment. Something else to consider on this topic might be the question "Are the engine/flywheel an original match set?".
My '51 currently still has the original 216 flywheel, but a later '54 235 my grandfather installed back in the early 80's.
When checking/setting timing in my case, I have had to ignore the existing "ball" marker and use my grandfathers added mark to get proper idle and performance.
Though I have an 261 and the rest is from a 235, the TDC and the BB are exactly where they should be - I measured it, when I rebuild the engine.
But that was not my question, just wanted to know if the Diagrams in the manual are already including the 5 (or so) deg BTDC of the BB or not - which was answered by Bill.
Background: The engine is so much modified, that the stock curves don't do the trick anymore, so I'm trying to tailor my own curves, but use the diagrams in the manual as a starting point and go from there.
The digital Ignition I use, works from TDC. So - if the curves would have included the advance of the BB, I would have taken that into consideration - now I don't have to.
best, Frank
