Not sure what you mean by "Class 2", I certainly don't think linking the bell tamper out is a good idea. This is the only protection from attack the external components have.
As above link the bell and strobe terminals together at the bell, if you don't wish to use extra features like engineer H/O etc.
Better still rewire it, if it's old four core it could have been in for years and may fail in the near future. Once a core goes down your rewiring it anyway.