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