Hello All - Newbie Here - wanting to share a recent find.

Recently I started experiencing backfires on my 454, so the first thing I did is read all the related threads posted on this board, and began checking the recommended items (carb, distributor, vacumn leaks, valve springs, etc).

After all the checks and still not finding the issue, a friend of mine recommended a method in which I have never heard of before (raised my eyebrow) and that was to pull the rocker arm covers, and push gently on each rocker arm while the motor was running. In theory, it should slap your hand if the valve is working correctly, and if there is a weak or damaged spring or retainer, it will show up.

Now I dont know (being new here) if this is a recommended test, but it worked! When my friend pushed the intake rocker for piston 1, the engine almost died. We compression tested the cylinder, and it was showing good compression. At this point we pulled the rocker arm off, and the two piece locking retainer was broken severely, but had one side still holding on.

The symptoms I experienced were as follows:

--Runs great at an idle
--Runs fine bringing up RPM's in driveway
--Starts backfiring under a load at mid-high rpm's (while driving)

Anyways - looking to replace this retainer tonight, but I am sure this is the cause of my issue as all other components checked out. Thanks for all the great info on this board, as I made it a long way diagnosing the other componets to find this issue.