can they be reuse again?

 

yes unless you torqued them to 100+ foot-lbs

 

I'd hope he torqued them to 100+ft lbs

 

It depends. They weren't torque to yield bolts right? As long as you did not exceed the torque specified by ARP and you used the lubricant they specified on the threads when you installed them you should be fine. Inspect the threads for damage and if there is any replace the bolt. You should not use a die on the bolt as it will seriously weaken the threads. The threads on the bolts are rolled and if you cut them with a die you will create stress raisers.