While it might be difficult to establish unless we have more data,
I dissagree with that comment completely. i've used stock block in well over 550rwhp reliably for long times. When carnage like this happened (usualy #5 or #7) it is 80% of the time a lean condition. Those stock pistons can take a lot of abuse.
I've run 12:1 setups with juice with no failure. But lost 2 motors to lean cylinders, 1 because of stuck nitrous solinoid and another due to failed injector.
Another main cause of stock block failure is rod bolt stretch which sends the piston crashing into the valve and if at high rpm can result in the carnage you see. Being it is neither #5 or #7 on this block, that could be the cause as well.

 

There is a good sized hole that you can see in the cylinder....This car needs a new shortblock and some head work at the minumum...

 

I can understand something happening like this to a boosted motor, but mine is N/A

 

What caused this to happen to yours?

 

I would go 383. Jason from thunder put together a mean little setup using 5.3 heads.

 

I think that I might try to go with an engine size that will complement the Trick Flow heads that I have already since it looks like we will be able to save them.

 

Did you run the car without a tune for any period of time, i have heard it isnt very good to run an engine untuned for along time.

 

The car was never run without a tune, although it took a couple sessions to get the tune where I wanted it to be.

 

Not what he meant-

Common with the boosted/nitrous guys, the same type of thing occurs.

 

Just tore the shortblock down about 2 weeks ago and found the bearing spun on that rod. The missing bearing material allowed the piston to crash into the head and possibly the valve. I was surprised to find this b/c the oil pressure was good and the engine was not making any audible noise prior to letting go.

 

What I was getting at is if he made the numbers he did using 5.3 heads, im sure you could do equal to or better with the TFS heads. The two motors (346 and 383) have the same bore, so it wouldnt require the purchase of new heads either.

 

Crapy...MAN am i gonna **** my self when my engine decides to pop....prob scare the living hell out of me when it goes.

 

I meant you'll need a new block too. I said it would only run you around $150 used. Bore it +.007 and slam some new pistons in that sucker.

 

When my buddy did the Heads/cam swap on this car, he noticed an abundance on metal shavings on the drain plug when he drained the oil. I would say this happened due to some type of mechanical failure.

 

Ring failure. Judging by the look of the valves I would say this is more likely than a lean condition. It would help to know what the plug from that cylinder looked like.

 

Your wallet's life will flash before your eyes.

 

what inj.s are you running?

from the start, reading all the way through this, I def. agree with the point predator brought up.

might want to test them and make SURE your inj. didnt lock up and cause that cyl. to go lean. these hyper. pistons are very brittle. as in they shatter into a million pieces when they let go instead of just crack or break.

 

lol THAT and the loud scary BOOM its going to make when it happens...

 

So can a faulty injector (one w/ 130K miles on it) cause a STOCK motor to go so lean as to destroy a piston?

Does this mean that one day, because of a partially clogged injector, I will rev it to 5K rpms and have it go lean to the point of destruction?

 

Well at least after you are done it will be a stronger and more powerful motor. Also, this is a good learning experience.

As far as the tune, maybe we can make a trip somewhere and have it done when everything is complete......