guys i know it should be forged all the way. but ive built engines with cast cranks and cast pistons for yrs and ive only had a few come apart. and when they did they were gettin old.ive left the line around 7000 a few times and missed shifts(cheap shifter) and watch my 12,000 grand tach say 10,000 and still drove it up on the trailer to go home. but ive also sweep up a few ponds of metal for the trash man too. but mostly they stay together. dont ask me how but its true.ive run 13.1 pistons on a cast crank.stayed together. that did come apart one day when we decided to put the juice to it and it had a tunnelram on it so we gave it a little to much i quess,cause thats one of the ones i swept up..lol should never smoke pot and think about cars.ever lol.. but i was young so what the hell it was only money and metal!!!!!!!! and a whole lot of fun!!!!!!!!!