Due to the need to obtain proper/limited compression of rubber parts, it is done by measurement, not torque. Except in cases where there is a metal sleeve to control the crush/compression.
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0102.htm

For normal grade 5 fastening: 3/8 course torque is about 30 Ft Lbs and 1/2 course is about 75 Ft Lbs. This is a general torque with no rubber involved. Torque charts differ due to plating, grade, dry or lubricated.

The answer is: tight, but not too tight. smile If there are split lock washers, they need to be squeezed flat.

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