If anybody cares, please read.
I let it overheat with the new bolts on, confirmed with fingers the heatsinks was very warm, then turned it off, after 5 seconds, then turned it on, the 360 worked. Then I screwed the bolts tighter, may have been too tight as per instruction saying to tighten them after burn in. The screws then seem to have been much much looser after the burn in, mobo was really bent badly? I turned the 360 on, and got 3 red rings again. I left it on to overheat again, but I touched the heatsinks and they didn't feel warm at all. So I removed the heatsinks, turned on the 360, touched the chips, all the chips, none were warm, none were hot. I check the GPU, saw one little, tiny resistor off the pads, I tried to solder back in, but it's impossible since it's so damn tiny. So mobo is completely dead now, still 3 RROD.
So I believe the screws method would have worked for mine if I hadn't screwed it so tightly.
I recommend not to retighten them once you see 360 is working.