Timing issue

[951mat]

I'm stumped on the mechanical advance of my MSD on my 427. Very simply my initial timing right now is +/- 12 degrees. I have the 2 light silver springs and the red bushing in my MSD distributor. The red bushing should deliver 28 degrees of additional advance for a total of 40ish.

My timing all in is only 25 total at 2300+ rpms. What gives????? By the way, if I set my initial timing much higher, starting is much more difficult and the engine "runs on" after shutting down, I assume because of the pump gas its on. I don't think any of that really matters with the main problem of my total timing not adding up. Any way to trouble shoot this?

Thanks for any advise.

Mat