If you are asking about the sprocket bolted to the front of the cam, you would need to remove the timing cover and remove the 3 bolts on the front of the sprocket.
If you are asking about the gear on the back that drives the distributor, it is integral and cannot be pulled.
Just pull the camshaft gear of it should be just 3 bolts
very carefully
the block & heads are the same you just have to pull the 305 out & put the 350 back in
it takes 2qtsof gear oil
remove distributor and check the gear on it.if gear is ok then remove front cover and check timing chain or broke camshaft.
YES
YES.
YES it will there is no difference in the design of the camshaft.
It is a hydraulic camshaft, Not a roller cam. Chevy did not start using roller cams until late 1995
If the Buick 305 is really a Chevy 305, then the motor mounts will interchange with a Chevy 350.
I believe 88 and earlier 305's have a nylon coated cam gear that is supposed to make them run quieter but are prone to failure, however chain and crank gear are all steel.
Back of the motor near the fire wall. Follow one of the wire sets from the distributer to the sensor.