I've been running a KB gear set for about 12 years now on my 2 race engines(small blocks)... no noise and timing is dead steady... just have to set the back lash on the idler to the specs and drill and tap 1 hole... They are pretty nice... loosen a few screws and you can change the cam timing(degree marks on the cam gear) I also have a KB for a BB as well as a aussie belt drive which is new... I'm in the process of selling off my BB stuff