Is it absolutely necessary to measure rod bolt stretch or can arp rod bolts just be torqued?

 

The stretch method is the correct way.

 

The stretched method is the best and most correct way but ARP can provide you torque specs when using their thread lubes that'll match the stretch measurement.

 

^^Agreed. Stretch is best, but not absolutely mandatory.

 

When I installed mine, the specified 75 ftlbs gave me between .004 and .005 stretch. Increasing torque to 85ftlbs still didn't get them all to .005. Out of fear that I would clamp the rod too tight and lose bearing clearance I cried uncle. I called TSP and they agrees that I was best off leaving it as-is, though that doesn't mean that would be the case in a different situation.

 

A good friend of mine who is a pro LS1 builder from a very reputable shop says its not necessary. He uses the lube and proper torque and that's it.

That being said, I just purchased a stretch gauge and I plan on using it. But I'm something of a nerd about these things...