[72c20customcamper]

Originally Posted by dave6672

I'm very interested in replies to this thread. I have a 72 C20 with a 350 that sat for many years before I purchased it (truck only has 25,000 miles on it). I oiled the cylinders, let it sit and then turned it over by hand prior to starting it. I got it running real well but it has had continual lifter noise for the past year. I added MMO to the oil initially and after 100 miles or so changed the oil and added Rislone to the oil. Neither has helped the noise but it has been running great so I didn't care.

Then the other say coming home from work it wanted to die every time I came to a stop (won't idle). Looked for vacuum leaks and ignition issues but can't find the problem. I then noticed an "air puffing" type of sound from the tailpipe that wasn't there before and am wondering if there is a valve train issue? Therefore I am definitely interested in any types of additives that I could use to solve my issue.

Could have burnt an exhaust valve.

To OP if the valves are sticking I have used mmo and pb blaster to lube the valve stem . On a 6 cylinder I once had to actually tap the valve and spring with a hammer and pry it back up. This was before I got the engine broke free. A 63 lark with 22k original miles . I bought it in 1980 the car had sat untouched in a basement garage since 1968. Have to say the car ran great after a few hundred miles.