I built my stroked 340 with a clean std bore '71 block back in 2008 so my original std bore numbers matching 340 could be set aside and not take risk of grenading blowing apart. Back then the 340 block cost me $500 and it was exceptionally clean. That $500 was a very small percentage of overall engine cost and I could say I have 340 block in factory 340 car. Things have changed over time where makes more sense now to use the cheaper 360 block as a starting point.