[25stevem]

This is the kind of timing profile that was commonly used in the mid 60s on 4 bbl motors of 350 hp or more and stated to need to run on the high octane fuel of back then.

I would start off with 3 degrees less total timing then this at full throttle ( no vac advance) between 4000 and 4500 rpm.

For vacuum advance these days it seems that a max of 12 degree should be observed.

As posted above it's different for every combo, but one thing you can count on is that the longer / closer the stroke of a motor is to making it square, and or over square as in the 455 the slower you will find you need to have the mechanical advanced kick in and not detonate.

Your 3.73 gears will help a lot in that the motor will not lug as much at low rpm's until it comes on the Cam.
This should help you with getting more responce to take place by putting in more timing faster.

Those heads on 3.750" stroke motors and the the proper octane seem to do will with 40 degrees total , but take your time and find out what your combo wants.

All this being said I would invest in a add on knock senor to guide you.