If you are racing, why push the limits of the stock crank? It's plain old 1053 carbon steel with undercut journals. For a few hundred more, you can have a 4340 alloy steel crank with radiused journals that is at least 50% stronger, maybe 100%. If you break a crank, you could wipe out the rest of the motor, you could dump oil under tires and wipe out your car, and maybe get injured or worse. It's one of the things that costs so little to upgrade, just like stock rods vs. aftermarket, I don't mess around with 50 year old production line time bombs.