351W ignition timing

The 351W in my Bronco had the timing set at about 22 degrees BTC when I got it. It runs well,pulls strong, does not overheat and starts easy,but that timing seems alittle too far advanced to me. I do not know how the engine is cammed and I know that will make a difference if it is a stock cam or not. Also at this timing setting it holds about 18 inches of steady vacuum. I would like to get some opinions or suggestions on this. Should I leave it set where it's at or should I change it ? What is the stock timing for a 351W ? Thanks

6-10*deg is normal.18 in. of vac is good.with that vac,it is not much of a cam over stock.probbly a good rv type.disc vac advance and see if timming changes.if you get a big change,you might have it on full manifold vac.but if you like the way it runs leave it alone.vacume advance usually gives about 10-15 deg's of advancebe a good idea to check it out for propper function anyway.

Leave it alone! If it runs good, don't fix what's not broken

Thanks,the one thing I failed to mention is that it has an MSD ignition with a centrifugal advance dizzy. There again, I don't know how the advance mechanism of the distributor is set up. Thanks again.