I have a Summit Racing Engine bolt kit for SBC. The bolts are Stainless Steel Grade 8 bolts. Part # SUM-56490HS. Most of the bolts are still in their packages unused. I used a couple of the bolts on a motor I had on an engine stand to cover up all the motor's open orfices to keep moisture from getting in it. The ones I used were a couple of intake bolts, fuel pump bolts and the header bolts. They were never on a running motor. All the threads on the ones I used are perfect. Obviously the ones I didn't used are still in brand new condition. All the bolts and washers are all back in their original bags. I am not going to use them now.
They go for $36.95 I'll let them go for $20 plus shipping if you are not local.