Are the towing eye bolt threads on the 451 the same as the 450, i.e. Acme thread? The Acme thread is designed not to bind or seize, so that it will easily come undone once the temporary use is over.
For this reason, I would again suggest that this bolt system not be used for the purposes described in this thread. Even if you torque it up "tight", it will come loose due to its special thread angle, seat, and shoulder - that's what this special configuration thread is for, and why I expect it was chosen by the engineers for this temporary towing eye application. It is easy to start the thread, fairly tolerant to minor grit etc., and easily removed without applying loads of torque.