This ^^^^^. Everything has a life span. As I said, in a N/A build, .100 under and you'd never know the difference. But the fact that the crank is an original forging, decades old, you don't know what it's been through, plus you're talking about going .030 on an engine with a very high power output. If ever you were trying to find the crank's failure point, that would be it. It's your money. Run it if you want to. You can get a nice crank for around 700 bucks. I would hate to see that engine destroyed because you didn't spend an additional 700. What have you got in it? 5 times that? More? Think about what you're doin. Even if you have to wait to save the money, it's worth it.