No they are not.
If the Buick 305 is really a Chevy 305, then the motor mounts will interchange with a Chevy 350.
The headers for a 350 and 305 are the same.
the block & heads are the same you just have to pull the 305 out & put the 350 back in
no on a 350 it is on the driver side and on a 305 it is on the passenger side
yes
yes
305 is the same distributor as a 350 will even fit some big block chevy's.
Yes it is.
same as a 350
yes
NO The bore and stroke is different.
Yes it will bolt right up, no problem. As long as the 350 is close to the same year as the 305.