It is not the weight of the bullet, but the powder load that determines if it is too hot or not. Factory .38 S&W are loaded with 146 grain bullets and are safe to shoot in a good condition top-break.

If reloading an 80 grain bullet, make sure to use published data and do not make stuff up, since too much powder can lead to high pressures even with a light bullet. I have not seen loads for 80 grain bullets in .38 S&W, but if velocities are below 700 fps, you should be good to go.