Tear down your valves and make sure the valve seats aren't damaged where the bent valve came in contact. My need to lap new valves to the seats. Also better check that piston over really well for damage that could come back to bite at around 7000 rpm's one day. Sorry to hear of your damage. Don't know if you have replaced springs or not but this could have been caused by floating valves as well. If you are going to do it why not look into something like this.
http://www.ebay.com/itm/180705617664...84.m1423.l2649