On my volvo, it's suggested that the head bolts are replaced when rebuilding.
Does the same go for the tension bolts on rotaries? Should they be replaced when doing a rebuild?

 

Tension bolts should be fine to reuse in a rebuild.

 

unless you're trying to make 700+ hp then, they are fine to reuse

 

They are not torque to yield like many head bolts, but instead made of spring steel because they need to compensate for the engine expanding and contracting as it is made of alternating slabs of aluminum and steel. Fine to reuse.