5 quarts with filter change is normal. But there are exceptions, especially in 4wd vehicles. Change the oil & filter, pour in 5 qts., start the engine and run for 1 minute, shut off and wait 45 minutes, check the level and add as necessary. You now know the capacity.
roughly 4.5-5
5
6
Yes.
5 qts with a filter change.
5 with a filter change.
zero
yes the 4.3L vortech has the same motor mounts as the 350
If the Buick 305 is really a Chevy 305, then the motor mounts will interchange with a Chevy 350.
About 4 quarts. I put in three and then check it.
6 Qts of oil
5 Qts. with a new filter.