Engine in 85 K-5

[MudDragon]

Just bought my 85 at an auction. Got her home and cleaned off the engine to find valve covers that have 350 printed on what should be a 305. What is an easy way to tell which one I have?

 

[95 Silverado]

look in front of the right (passenger side) cylinder head on the engine block, behind the alternator there should be a small pad with some numbers stamped on it, this will show the original engine code, it can lead you to what size it is and what it was originally installed in.