Another timing curve question

DrCharles said
Today I hooked up the timing light again... turns out I had slightly underestimated the amount that the superlight spring advanced before the heavy loop engaged. So there was hardly any advance left because the FBO plate was hitting the stops at 18.
I experimented by removing the plate entirely (26 degree slots in the dist). And it works just about perfectly... idles at 27, starts slowly advancing at (estimate by ear) 1800, up to 35 by 4000, and I didn't rev it any higher. Thought it was screaming but the tach recall said not.
The ported vac advance doesn't kick in immediately as the throttle is gradually opened (I think AJ expounded on this in a different thread). My can is an "8L" i.e. 16 deg max, and I got just about to 50 revving it unloaded (17-18" vac.) May try it with full manifold, since my idle vac (8") won't pull the can in anyway.
So my timing may be pretty close, and I can always retard it a couple degrees from the dash (0-15 degree knob at my fingertips) if it's too much on the high end... May not have to send it off to @halifaxhops or YR :)
Now to get back to tweaking that crotchety 2-corner-idle carb since I've altered the timing!
:thumbsup:

I love the fact you are grinding it out. I love that. I know many guys smarter than me (Tuner for sure...shrinker is another and many, many more...Joe Sherman also said this, but I only know Tuner personally, the others I've read what they have posted in other forums) say that on the dyno of you don't check the timing at the RPM the engine will see while running you're not getting it timed correctly.

While 4K sounds like it's screaming, if you plan on shifting at 6k or whatever, you may want to put someone you trust in the seat and let them run the throttle while you run the timing light. Have them start at whatever RPM you think (in your case I'd say start at 4K because you've already been that high) and have them go to 5k take a reading, let the engine come back down (reduces the blood pressure a bit!) and then go to 6 and do that until you hit the max RPM you'll see.

That way you will KNOW where the timing is, and if it's not what you want, you can correct it.

Just my .02