Physical chemistry, yes. Emotional chemistry, no. I can kiss a stranger I've never met and it would feel like kissing a door. After we get to know each other however, we might "click". But for me, it would only be on a friendly level if that was the case.
I understand what you mean though. A great kiss will mush your head and will tell you he's probably a good lover. But if there's nothing else there to hold on to, that's all there will be.
Since you already have an established friendship with this person, there already is a chemistry, so when you do kiss, you will feel something because you are already priming yourself for it. Don't lie. It's all over your face. Well, I can't see you but I feel you planning out a wicked scheme to get this done. Let me know how it goes. And good luck :)