Will the heads off a 1995 Chevy 5.7 fit on 5.0?

No, the heads from a 1995 Chevy 5.7L (350 cubic inch) engine will not fit on a 5.0L (305 cubic inch) small-block Chevy engine. While both are small-block Chevys, the 5.7L and 5.0L have different deck heights and cylinder bore spacing. The bolt patterns may even be different, depending on the specific year and generation of the 5.0L. Attempting to install them would require significant and likely impossible modifications.