So I am reassembling my engine and I decided to reuse the stock rod bolts. I over tightened them do to them probably stretching over th years. I can sill turn the crank. It's hard but does turn. Should I be worried about my engine not being able to perform like I want it to?

 

Always tighten such bolts to the torque value specified in the FSM or similar manual such as the Haynes Z31 repair manual. Using old bolts is usually asking for trouble. The bolts are stretched under torque and often become brittle with use.