Hm-m-m-m, don’t understand why you can’t hold the flywheel. But anyhoo, the torque to tighten the nut is 60-65 ft/lbs on your 1952. Aftermarket ignition parts have been getting a lot of bad press lately. You probably should get OEM parts from an Evinrude dealer, or at least another source selling OEM parts. That would include several members that you may hear from.