What is the key number(s) to consider when looking at compression ratio? For example, 8:3:1. By looking at the compression ration alone, does it tell me anything? or do I need addtional information? For example, 8:3:1 @ 362cc's.

Or is the bore/stroke more important in terms of helping to determine an engines performance? For example: 8:3:1 @ 362cc's, 80.0(Bore)X72.0mm(Stroke).

 

All by itself with no other info the compression ratio doesn’t tell much. For instance, an 88 LT500 with a 6.3:1 compression ratio would smoke an 88 LT250 with an 8.0:1 ratio (those are stock #s if I remember correctly) despite the higher compression. But if you had 2 identical Quads and raised the compression on only one, it would then have more HP than the other. Like if you raised the compression of a LT500 to 8.0:1 it would be more powerful than the stock LT500 with the 6.3:1 ratio.