If you actually SPUN the main bearings, then you can not simply just regrind the crank install the correct size bearing for the grind and put it all back together. You will also need to have the block line bored to make the crank cups true again. Just like if you spin a connecting rod bearing you can't just regrind the crank and put in new rod bearings. Really with the amount of time and money that is involved with that you are better off with at least a new short block. Or you can buy a whole used engine and install it.
