I ran into this recently with Crower rods while checking bearing clearances. The torque spec does not equal the stretch spec. First I torqued the bolts to spec and then checked the stretch. The bolts were not even close to the required stretch. Then I checked the clearances with a bore gauge and they were good. I tried tightening the bolts using a stretch gauge and it took a lot of extra torque just to get to the minimum stretch requirement. Seems like more than an additional 20 lbs of torque. Then I checked the clearances again and they were way too tight. It seems like going by the stretch method distorted the big end out of round and closed down the clearances. It seems to me that when Crower machined the big ends the caps were torqued to spec not stretched to spec. I spoke with a few Pontiac engine builders who agreed with me. When I put the motor together I’m going with torque. Strange thing is years ago I put together another motor using Crower rods. The torque almost equaled the required stretch. I only had to give the bolts an extra bump with a wrench to get the correct stretch.
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