Here is some info on what I used on my set up, and the part numbers if anyone is interested. Now keep in mind this is for the 6 speed, not the 5 speed. The parts I used were HD Japan model belt Part # 40056-07 Its listed in the parts book, it is a 136T belt compared to the 137 T stock one, it is an actual HD part made for overseas. It can be ordered at any moco dealer.
The pulley is an Andrews 30T sprocket Part# 1201-0227, which fits 07 FX/FL series.
This to me was the perfect set up, when stock riding solo the engine would die in traffic trying to clutch in 1st gear. I could also lug between 65 and 105 mph in 4th gear.
With this change I could use all the gears on the freeways, I cruise at72- 75 in 5th around 4000 (I forget now its been a long winter for me) and at 3000 in 6th Im cruising around 75-78. 2900 is the min recommended rpm with my cam/build.
The difference felt like I lost the top gear in speed, but could now use all the gears. I could run 75 in 5th at a nice range in the power band where a slight twist you will feel the torque, or at 75 in 6th you will get better mileage and not as loud exhaust.
The only drawback is my speedo is off 4-7 mph (70 is 65 and 110 is 104). :O( But its not a big deal, I was told that 1-1/2 years ago after I picked up the bike because they didnt have a kit to adjust the speedo at the time, they may have one out by now. It reads faster than actual. I did find a speedo calibrator in JP catalog, it was $110, it just plugs in the speedo wire coming off the trans, I havent put it on yet because I havent found the plug nor had time to look for it. All you do is install it in line its plug n play, it has a button up and down to calibrate your speedo. I have a GPS to use as a reference.
I have about 15k on and no issues.

 

While doing a search on the 510G Cams, I found this thread. This is all good info - thanks for sharing.