So me and a buddy jacked with them today. Weird deal ALL the ones that were tight spin right down perfect upside down! Spin right down on my thread chaser but those are a little loose anyways. Some are a little snug on a new 7/16 Grade 8 bolt some are not. ARP nuts spin fine on the new Grade 8 bolt but are even worse on the rod bolts. ARP nuts look a hair larger OD on the shoulder and not sure there is much extra room o the rods.
Mixing and matching the nuts we got most that are pretty good. No "dimple" for rod stretch gauge.
It looks like maybe previous off and on dinged the nuts a little and when the big ends got a little grinding the end threads on the bolts got just barely touched. I think it is mainly really tight tolerances on the threads and slight dings adding up-why swapping them around worked better!
Man these Crower rods are heavy 907 gms! Plan is to go in an extra parts 455 anyway-for dyno testing soem different dual quad intakes M/T, Warrior and the new Bathtub.
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Skip Fix
1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever!
1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand
1965 GTO 4 barrel 3 speed project
2004 GTO Pulse Red stock motor computer tune 13.43@103.4
1964 Impala SS 409/470ci 600 HP stroker project
1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs
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