Forged 273 crank in a 340 block

hi, you cannot grind out the register!!!! it has to be machined in a lathe. it has to be dead on in relationship to the center of the crank, or it will vibrate and will destroy the rear main bearing and the front pump in the trans. I have machined a 273 to fit the larger converter snout. it's not for the average guy to fix. a machine shop is your best bet, for an accurate job.