My last 440source 500 lasted (275) passes running 8.60's-8.90's in my Daytona before it split the block and I found it during a Winter tear-down. That assemble is still running in a street car today. I have a 512 440source assembly that will be going in a duster in the near future. I don't spend waste any money on fancy band-aids on my blocks so my block machining costs are minimal. If it last 275 runs again I will gladly scrap the block and have another one machined. All my builds have been with 440 blocks.