@Mud, you've pretty much got the answer to your question spread over several comments so I'm merely consolidating it here in a single answer.
On the 7600s/6500s you can filter BFD (control-plane traffic) at the interface level just like any other traffic (transit traffic passing through the device).
When you apply an ACL to a port on the line card its applied to all traffic on that interface. Traffic that needs to be process by the RSP or DFCs if you are using them needs to be punted there which is after the ACL is processed.
As a rule of thumb I have been including control-plane traffic in QoS policies of late, such as the following where "class NC" matches CS6 & CS7 only:
bandwidth percent 2
police rate percent 10
priority level 1
bandwidth percent 22
bandwidth percent 24
bandwidth percent 12
....... and so on
If you write a CoPP policy for your 7600s/6500s you need to write ACLs that match all your relevant kinds of control-plane traffic. So you can also match BFD traffic by matching traffic to/from UDP port 3784 (and lock that down further to your interface IP if possible).
As @ytti said you need to be wary of the BFD timers on your setup, if you haven't got DFCs your running BFD on the RSP/CPU power. In that case you might also want to look at tweaking you "process-max-time" global command and the process schedule "scheduler allocate xxx xxx".
The Cisco recommended minimum is
bfd interval 100 min_rx 100 multiplier 3 but on some production boxes without DFCs I am actually running
bfd interval 500 min_rx 500 multiplier 3 which has been fine, I think on the boxes with DFCs which I don't have access to right now I'm running the same.
You can see these references for more info, which cover BFD tuning and ACLs for control plane traffic (both CoPP and interface ACLs), and also some control-plane tuning that is generally good practice, also QoS behaviour with control-plane traffic: