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hi
Have a 72 GMC stepside with a 402, TH400.
drove home and ran like crap. bought it that way.
did comp ck- # 5-6-7 at 25 lbs. pulled valve covers and all intake valve push rods on those cyl. bent. some rockers were sideways. I know I have to pull heads but does anyone have any ideas. don't know if pistons scarred and if valves bent yet.
thanks for help
Sounds to me like the PO foated the valves in a "high RPM excursion". Pulling the heads to assess the damage is about your only option, seems to me.
Last time I saw bent/broken push rods it was a wiped cam. But it wasn't all of them at once.
With 25 psi compression, I would say that your chances of undamaged valves are pretty near zero. Good luck.
Not to mention that those things (early 396/402, as well as other early Rat motors) kind'a like to eat cams if they were not treated just right. If you find that you need to replace the cam, a highly likely situation, consider going with a roller lifter cam and conversion parts, it will live a lot longer next time if you do that.
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Back in Bus. came back the day after he posted, saw one reply and hasn't logged on since. I hope he's maybe checking in as a guest and will come back and tell us what he found, assuming he's pulled it apart in the past 4 months....
Huh; yeah, Roger, he's long gone. I didn't look at the date of the original post.
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