I just measured them and they measured 1.345 between the piston bosses. I don't have a rod to measure. Engine is still assembled and isn't tore down yet. In the How to build Big Inch Mopar Small Block book, it says that the Magnum Rods are narrower than the LA Rods at the small end and the LA rods are 1.200. The Magnum Rods should fit?