1978 Chevy 305 oil sender location?
It should be in the back of the engine, just to the drivers side of the distributor.
Subtract 305 from 350 and that will give you the difference (or interval) between the two numbers:- the answer is 45. However, if you mean what is the difference between a Chevy 305 and a Chevy 350, then it is the difference between the engine bore (the cylinder) sizes. The 305 bore is 3.740 inches. And the 350 bore is 4.000 inches, giving the Chevy 350 20HP more then the Chevy 305.