Thread: 5.5 head
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Old 09-02-2023, 04:12 PM   #20
ModelA29
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Default Re: 5.5 head

Quote:
Originally Posted by Ordsgt View Post
...I replaced all the studs and nuts with harder ones, they were grade 8. I...the studs and nuts were like new despite being in the car 2 years ago.
New grade 8 studs have a much higher yield rate than the originals which were probably grade 5. They all rely on some stretch for their holding power. The grade 8 stretches less so it doesn't fatigue as fast. Most newer cars torque the heads 90-100 ftlbs and at 55 lbs the grade 8s should last many rebuilds. Has anyone tried 55+ lbs with the new bolts? My 289 HiPo would blow the gaskets at the stock torque but 5 pounds extra and the problem was cured.
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