Hey guys, first time poster and hopefully a soon to be G-Body owner. A guy close to me is selling an '81 Malibu. From the pics he has sent it looks to be a pretty solid car, but the trunk has holes and the bottom of the driver's door has rust as well. I asked about the rear frame rails and he says they are "getting soft". I'm new to dealing with rusty frames and need some pointers, maybe even some pics, of what to look out for. I've heard a good trick is to give the frame a few hits with a 5lb sledge and if it makes a ping, its ok. Is this accurate? Thanks for the advice guys!