Head Bolts and Exhaust Manifold Studs

krazykuda said

All head bolts will stretch slightly when torqued. It's very little and can't be seen by the eye. You need to have the bolts ground flat on each end with centers drilled, then use micrometers to measure the bolts before torquing, then remove them after torquing and measure them again to tell how much they stretched.

It's not easily done at home in our garages...

But they do stretch a few thousandths of an inch on average each time you torque them...

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Yes, all stressed fasteners stretch, they are " linear springs", very stiff ones. But good
luck checking the stretch on a head or main bolt/stud accurately, lol. All rod bolts where
the spec is given get torqued that way when I build an engine, the rest depend on good
preparation of the threads and fasteners, and an accurate torque wrench/procedure.
Yes, there are a number of aluminum headed engines that seem fine w/o TTY style bolts.

The upshot for Glueman is.... clean the block threads, run your headbolts on the wire
wheel, and proceed ............ :coffee2: