Where did you get the hood from???
Wildcard, I dunno if you want to gear down. I have tried 20/45 Don't like it. I am going back up to 22/44. The 670 is a Torque monster. Ohh wait, you got a triple. Thats rigth. Well, I have a 45t bottom gear if you want. See, my 670 pull's like MAD in the mid speed area. Really falls flat up top. It LOVES to be loaded up. I have a bud here who has been running 670's for many years. Now has a 153" ZX based 670. Pic of his sled is on my Powdercoating wweb's picture gallery. But anyways, he is runing, and has said 2:1 ratio for the 670. They need to be loaded up. I got 20/44 on there right now, and the 22T is in my stocking for Xmas. We will see.
The reason all the REV's and XP's are geared down so low, is
1) they run 10 tooth driver's, larger diameter to start with, needs lower gearing.
2) they have a MUCH narrower Power band than the old 670's Thats why they allways struggle with clutching. They need the lower gears, to help the engine reach and stay in it's powerband.
I will post my results once I change the sprocket.