I had a 1970 340 block that I raced and it eventually made 602 HP on the dyno. I ran it for several years until the main webbing literally split the block in half! It had 4 bolt mains installed and all the other tricks done to it but it just could not handle that power run after run. It did run 9.50s @ 138 MPH shifting at 7900 rpm. 3.58 stroke crank in it. Naturally aspirated. I had a lot of passes on it over the years and refreshed it every year at the end of the season. It started out with W-2 heads and then W-5 heads which made way more power and it only lasted for 40 runs when I went that route making 602 HP. I have since went to an R3 block W-9 heads and have never looked back.
