buckstix,
I believe it will be harder to modify a press dimensioned only for 7/8" dies, to accept 1 1/4" dies, and in the end the press may be ruined.New presses to fit your dies(will have a 7/8" insert)will be fairly expensive.They can be found in the used equipment market, at a much more attractive price.Several different "makes" have models that will work, including RCBS, Herter, Lyman, and maybe others.It dosent hurt a thing to have more than one press( I have 5-my grandsons will be in good shape).
Mike