Base Timing

[C.Fisher]

Stock 300 hp 454 with Holley/B&M 250 scharger what base timing shold this run and what total timing @ what rpm? Max boost is 5lbs. This is the stock Mercruiser/GM ignition as well.
Also what rpm should these engines idle at 800??
Is it common for a supercharged engine to loose boost at max rpm in our case it is 4500? Basically what I am saying is when under load it will hit the 5lbs until it reaches full throttle "4500" then it will start loosing boost.
Sorry for all the questions
Thanks in advance
Chad Fisher

[SmokinLowriderSS]

Pick a spot anywhere from 8 to 12 degrees (I'd say 10) considering fuel today. Don't let it advance beyon d 36 or 38 when it is all in.

[C.Fisher]

Pick a spot anywhere from 8 to 12 degrees (I'd say 10) considering fuel today. Don't let it advance beyon d 36 or 38 when it is all in.
Thanks Smokin, I think I am getting this all figured out now.