The block doesnt need sanding just clean it well, and you can sand the valve covers with 320 grit, buy some bulldog adhesion promoter and spray it on the block and covers before painting, and yes hightemp paint wworks fine, one thing that i forgot is scotch brite pads before sanding anything go over it with scotch pads to "rough" it up, use the purple or green pads, all you have to do is shake the dust out of em and reuse, you can use em on the motor and stuff as well if you want to, use the scotch pads before wet sanding, if its been wet sanded dont use em and def dont use em iif you decide to color sand, dont forget to buy a tach cloth to wipe the parts down right before you shoot paint, its sticky and smells funny but pulls any small dust particles off the parts.