Timing curve for my big-cam 451?

DrCharles said
Thanks for actually addressing my question, Rat ;)

Yes, I'm aware of the unstable idle problem that would result from advance starting to come in at idle speed. That's another reason I used the heavy OEM spring.

As I explained, I can't start on initial over 22 without kickback and I do not want to have a separate ignition toggle or a start retard box.... and 22 is not enough idle timing for that cam. It idles much smoother and cleaner at 27... 30 would be even better.

So timing is 27 at 1200 and 35 at 4000. That is +8 degrees in +2800 RPM. You are suggesting I actually run less advance than that? Then I'd need more idle timing around 30-32 and still end up at 35@4000? Not too much for street use?

IMO, when you have one (or worse both) light springs as soon as you hit the starter it adds timing. That first jolt of the starter can make the weight move with a light spring. It may start with 26-27 initial if you get rid of the light spring. Also, I forgot to say that he slowing the curve down ask suggested I would bring in the VA sooner so you are getting some additional timing before full advance. I’m not a proponent of of using the VA to add timing at idle, so you can delay it I adds timing after that.