You will if you heat straighten it
aye, with the crank off the machine on vee blocks on bench, i'd agree. However being realistic, by the time you've got it that far, you're already in for the time, stripping it, then new gasket sets, etc, and the time to put it all back together all that for a hundred quid lawn mower.. Bearing in mind the high precision of the existing engine, I'd not waste my time / money going to that level, and would be trying it on the machine first, knocking it as straight as I could, taking the worst of the ding out and living with the rest... working on the principle it's already knackered, it can only get better....