Recently changed over to an S&S 510 gear driven cam set on my '03 FLHR. Glider is right about a bit more noise. But no big deal. At first I thought there was a new (small) exhaust leak somewhere, but in reality it was a new noise from the new setup. Can also hear it winding a bit like a turbo when ripping through the gears.
Did have to change oil pump because of the old HD problem with chain driven cams where the oil pump plate was damaged badly that happens on most all H-D Twin Cams between 30K - 40K miles. Replaced with HD Genuine Oil Pump. Feuling pumps are well-known and know guys that use them, but did not want to spend the added bucks.
Fuel economy, well, Glider is also right about the added performance and I have been a bit hotter on the throttle. Do not think there was a big difference.
The 510 cam is like the first step up from the stock cam which I think is around 502. The 510 is designed for heads that have not been ported and compression is less than 9.7:1. Got the S&S 510G Kit which retails around $700. In my guesstimate, gained about 10 HP.
Again, the change was needed due to failure of the chain driven cam and damage to the plate between the cam and oil pump. But am glad I made the change. Near the same time, put in a 6-speed tranny and with the two changes, I got a whole new girlfriend!
Good luck!
