If water is actually leaking there you have a bad freeze plug in the engine block... confirm by crawling underwith a good flashlight, the motor mount may have to be removed to replace......
Nope.
No they are the same blocks.Where did you get the mounts on the 350 from? The 305 or junk yard?Is it a new 350 or older 350?
because a 350 is a larger motor than the v6
Yes.
You will have antifreeze leaking out and dripping on the ground.
There is a freeze out plug behind it that seals the water jacket up. REPLACE freeze plug.
3/8-16
That depends on where the oil leak is, is it in the motor self or is one of the seals leaking?
sounds like you have a leaking head gasket
they are both V8s, they should use the same motor mounts
A leaking radiator hose would NOT cause this to happen, you have 2 problems with this vehicle.