chain drive conversion

I want to convert my bike to chain drive for a couple reasons. 1. I would like to go to a 180 rear tire 2. with the fresh power from my conversion the 883 gearing just isn't cutting it (as soon as i crack the throttle im hitting the rev limiter in first and second even though i pull some sick wheelies shifting into second) 3. I've allready been stranded by a broken belt and have a cracked sprocket at the moment

Now i have a quick question. Since i do alot of long distance riding mixed with a fair amount of hell raising what would make a good gear ratio for highway cruising (best engine rpm at 70 in 5th gear for example) Thanks for any help