Hi,
I'll start out by saying i overrevved the engine by accident just before i noticed the problem. I was accelerating and had a brain fart and didn't catch it until 5,700 rpm. Now redline is 5500 but the engine has only ever seen 5,000. But i would still think 5,700 for maybe a secord or two shouldn't be a problem, especially with only 56,000 miles. But whatever. I also have a loss in power. I was thinking bent pushrods, but it would seem to me that they would make a ticking noise not clunking. What else could it be? I would like to think it isn't the connecting rods. I mean with only 225 HP, and a low revving engine, i don't think it would be a problem. So please help me.

1987 5.7L IROC, 56k miles, stock

Thanks
JP

 

man, you got a sweet ride, she's beautiful in red
it happened to me and the clunking came from a bearing failure at the conecting rod #1, it was so lose that the piston was actually hitting the head and that was the clunking noise, i hope it is not the problem, cause in my case it meant overhauling the engine.
a good symptom will be low oil pressure, because, that bearing as it was, it was leaking the whole pressure right to the oil pan.
good luck brother.
Fernando.

 

Well oil pressure seems fine, but that bearing is definatly a possibility. I think i will check the push rods first just b/c they're easy to get to. If they're bent, is there any chance its only bent enough to cause a problem but not enough to notice just looking at it.
Thanks