Really hard to discuss when you haven't stated any of your timing numbers to begin with... more doesn't mean anything and Less doesn't mean anything because it's more from what point or less from what point.
An MSD distributor comes with 3 bushings... the largest diameter BLACK bushing will give you 18* of MECHANICAL advance --- so depending on your total timing desired -- you're initial would be 18* less than that. A BBC should handle 36* of total - so your initial would be 18*.
The TIMING CURVE is set by the springs... and their various combinations will make up what your curve looks like. This depends on gears - and cam - and weight of car and blah blah blah....
What someone would need from you is what is your initial timing - what's the total - what spring combo are you running - vacuum advance? Or not.... etc
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