351 Cleveland 2 piece valves

[Gud T.B. Blown]

Has anybody personally had these come apart on you? I've heard a few stories but so far they've mostly been anecdotal. Kind of like the lady with the dog and the whip cream/peanut butter in the garage. Meaning they heard of a guy who had a friend whose cousin had a failure.
I am asking because the tech I have working on my car never has. Now he isn't fluent in Cleveland so he's been asking around and hasn't found anybody that has had a failure that wasn't revving their car over 7k, which I don't plan on doing.
I have no problem replacing the valves but I don't want to spend the money if it isn't necessary for a street car, I have other places to spend it instead.

 

[Hack]

Go here.

http://www.network54.com/Forum/119419/

There are several members who had this happen. It can happen even with stock cam/springs. You definitely don't want to put heavy springs and a high lift cam with stock two-piece valves.

http://www.network54.com/Forum/119419/thread/1181086565/Final+Detail

There's a recent thread on this topic complete with scary photos.

 

[RogerC62]

Seen it happen. Was out with a friend who had a 71 Torino GT with a 351C. It wasn't stock but it wasn't radically built either. We were out playing and it started running rough. We headed back to where he stored the car. He shut it off when we got there. Got out to open the barn doors, got back in and it wouldn't start back up. We pushed it in the barn, popped the hood and pulled the valve covers. Found the #1 intake valve stem sticking down in the guide further than normal and missing the keepers. Pulled the head and found the rest of the valve in cyl # 4. We figured the keepers popped off. Needless to say it beat up the head, 2 pistons, 2 cylinders. I don't know what he did with that motor as I was on leave from the military at the time and had to go back but he did build a more radical motor after that for that car. Its just extra insurance to get the multi groved aftermarket valves & keepers just like doing the oil system mods.

 

[Gud T.B. Blown]

Go here.

http://www.network54.com/Forum/119419/

There are several members who had this happen. It can happen even with stock cam/springs. You definitely don't want to put heavy springs and a high lift cam with stock two-piece valves.

http://www.network54.com/Forum/119419/thread/1181086565/Final+Detail

There's a recent thread on this topic complete with scary photos.

I've been on that forum already but I wanted to get a response from somebody other than the hardcore racers since this engine isn't going to see that kind of use/abuse so I posted here as well. IIRC only one guy over there had a failure or only one guy who had a failure reponded to my post.
In the end it is all null. I got the intake and valve covers off and found out that the previous owner had already intalled stainless valves, dual springs, and upgrade rocker arms. Now I can spend the money elsewhere.