Thinking about a turbo slant...

If you use a carb your timing would be boost referenced. MSD makes a boost referenced box. It senses boost pressure via sensor of some sort.

http://www.jegs.com/i/MSD/121/8762/...&cagpspn=pla&gclid=CLTvtZ-65LoCFc9QOgodICwAjQ

http://www.jegs.com/i/MSD+Ignition/...&cagpspn=pla&gclid=CNqCs5-65LoCFZNlOgodMWQAjA