Compression ratio
Ok, I see you have not installed it yet. Ok, here's what you do. Take a spark plug out. Turn the engine until the piston in that cylinder is all the way up to top dead center, and then back down in the bore about an inch or so. Then get a light and shine in the plug hole and see what the piston looks like. Let us know is you see 4 valve reliefs, two valve reliefs or a single trough. It should be one of the three. Hell, you might even can see a part number. We can tell a little more after you do that.