I have been having some tuning issues lately.  I recently changed to a performer RPM intake and have had problems since.  First my valve train started making a lot of racket, and I had an overheating problem and a detonation problem that I did not have before.  I tightend the valves, not sure how tight is right, then I pulled my distributor and re-installed.  I think I was a tooth off the first time.  It seems to run good now, but I still have a little valve train noise and a high RPM backfirethrough the carb when under load?? Any advice would be greatly appreciated.

Hydraulic lifters should be set at one turn past "0" clearance. If the lifters are a bit worn, or really old, you may need to go a wee bit tighter.
If the valves are a little loose still, the backfire could be due to that. Take care of one issue at a time, and eventually, all will work out.
The overheating and detonation is probably related, but which happens first? If the engine is running hot, you'll definitely get some pinging, because the cylinder temps will be higher than normal.
On the other hand, if the timing is too far advanced, you'll get pinging, and overheating, for the same reasons. Make sure the timing is set according to the decal on the firewall, or the service manual, if you have it. That's a good starting point, as far as timing.

Another thing that can cause pinging, and a high rpm backfire is a vacuum leak. If all of your issues happened to start after installing the intake, you may have had a gasket slide a little off and there is a vac/ leak on the bottom side of the intake. Too lean of an air/fuel mixture will create pinging, and a vac. leak at the carb base, or a carb that is clogged up can cause a backfire.
There are other things that will cause backfires, such as a stuck/sticky valve, or broken/weak valve springs, or even valves that are adjusted too tight, ignition issues, etc...
Hope this gives you some ideas...

After re-doing the distributor I seem to have eliminated the overheating/pinging.  So I am hoping the backfire is from worn lifters, I plan on tightening them, I was unsure how tight so thanks for the guidance.  I will check that out and let you know.

As Joel said the backfire could also come from a lean carb condition at high RPM. Check and see if you are a little lean on the mixture and all your gaskets and vac lines are on tight. What type of carb do you have?
custom762007-09-29 00:13:44

Its a rochester Q-Jet, I think it needs rebuilt.  Do you know how to id this carb so I can get the right kit?

Driver side, rear of the carb, running bottom to top, you will see a series of numbers, starting with a 170, or 70. This is the carb ID that you need for the kit. There are also some other numbers there that are the julian date of the carb, but you don't need them for carb ID. Be sure to also get a new float for it, if you're going to O/H the carb.

                                              Q-jet ID # location