The 360 mag IS a tough engine if it treated right. The problem you describe is usually due to a clogged oil pickup screen causing oil pressure loss and airation. The pickup screen is only half the size of the LA 360 motors of years past, so they will clog easier. Check for oil pressure loss with a manual gauge not the POS in the dash first to see if it drops off at high rpm and comes back up when the engine is at idle.