Quote: never used an angle or bolt stretch gauge in his life on his ARP fasteners
the bolts / rods and slant six motors in general, are so beefy as long as you hit the minimum torque and don't go way out of bounds on the high side, the joint will live. If we were working with high end, very light weight modern parts that would not be true.
that being said, with parts from any source, there is always the possibility that the bolt material cound have gotten mixed or heatreated incorrectly and as a result, may have properties that do not match the requirement. Using fastners from a known source like ARP minimizes the possibility of bolt material errors, but anything is possible. If one were to measure bolt stretch of ARB bolts after assembly, the information would be additional data to confirm or dismiss the possibility of material or assembly error. There would still be error remaining, associated to the bolt stretch measurement gauge and technique.
Torque and angle when calculated correctly should result in a more uniform clamp load as it is a two stage process, as well it provids notice when some error is present that prevented the desired clamp load from being attained.
For example, I can run a two inch long bolt into a one inch deep threaded hole,, where the threads match properly, and hit a torque of 35 ft lbs, without the head of the bolt contacting the work piece,, remember this is a two inch long bolt going into a one inch deep hole,, zero clamp load at the bolt head.
On that same example, I could not reach a torque of 33.5 lbs and 180 degree of angle,, the bolt would bottom in the hole at 33.5 torque,, and when pushed to move another 180 degrees, either would lock up short of 180 or the head would twist off. This is an extreme example,, but shows how torque alone does not guarantee that the clamp load was achieved.
Using torque and angle gives more confidence,, is it required,, no.
Measuring bolt stretch gives additional confidence.
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