Any response from a mail-order diagnosis is going to be a longshot. There are so many variables that can cause engine misfires or noises so any suggestions are worth what you pay for them.

Instead, you should do some basic troubleshooting....troubleshooting 101....has worked for many, many years. Have you done a compression test? Looked at the plugs? Verified the timing and valve lash? Inspected the plug wires and distributor?

Dig in and find the problem...exhaust all the common causes...
before you ask for a list of "possibilities".