Fine threaded bolts are stronger and require more torque than course threaded bolts of the same size and grade. This is due to the larger minor diameter (deepest part) of the thread. I agree with bartamos that “Gr 5 is plenty strong enough” for our trucks but would replace like and find. If I found a fine threaded bolt, I would replace it with the same unless I found documentation saying otherwise.


Phil
Moderator, The Engine Shop, Interiors and Project Journals

1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube
Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes
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