The only difference between the two Chevy heads is the size of valve they were designed to fit. Either size will work correctly on all valves, though.
2825 - 194 = 2631
The 5.7 heads will work if they have the smaller 184 intake valves . Or you will have to bore the block over to get the 194 ,200,or 202 intake valves to fit into the cylinder if not it will lock it up when the valve opens and hits the edge of the block
There 194 heads 1970 to 1980 heavy cast iron heads
The 194 3.1 only
There is virtually no difference; term of protection is still based on the dates of the artist.
The engineered electrical resistance the higher the number the more resistance it can handle and vise versa.
Wattage. 194 draws slightly more than a 161 does. It therefore tends to be brighter when used in place of a 161. Both use the same voltage, just draw a slightly different current based on the filament resistance.
They are the exact same size and you can use them interchangeably. The diffence is that the 168 will be brighter than the 194. Although it is brighter, the 168 will not last as long (1500 hrs) as the 194 2500 hrs. - edit - The 168 has 3 candle power vs the 194 with 2. Since the 168 is slightly brighter it produces a bit more heat (3.8 vs 4.9 watts). In most situations where 194's are specified you should use an exact replacement to avoid heat damage from the hotter 168 bulb.
About 194 miles or 312 kilometres.