Was that dealership once named Massey-Brooks ? If so that is where my 70 Charger was purchased new . Still have copies of the window sticker , order and bill of sale.
How much strength did stress relieving add ? And is it simply heat cycling?
I started visiting the dealership in the mid '70's. I don't know if it may have gone by a different name that I didn't notice at the time or before then. Beach Street address on your paperwork?
Yes, it's my understanding that "stress relieving" is basically heat cycling to minimize any distortion after final machining. I remember reading something a while back about racers looking for unadulterated high mileage blocks to build on.