Never in all the hundreds of motors I've built including many that ran way over 7000 rpm would I ever, EVER dream of running an engine hard in extreme heat at 6000 rpm longterm on FIVE W-TWENTY weight oil!
Don't be surprised if the bearings are dead, that probably killed the other engine as well. You got all the earmarks of it.
If the pump looks good it IS, there will be undue wear on a bad one. You can't pump what is not there (almost zero oil weight).
No one in their right mind dogs an engine like that with no true oil pressure gauge on it, where I come from it's considered stupid. I mean mechanical not electric gauge. If the oil getting too hot you would have seen it in gauge behavior a long, long time ago. You would have also caught pressure flutters that disappear almost instantly too that would have alerted you to oil getting pumped out too if paying attention.
You are running water for oil that when it gets hot turns into less than water. And using a stock light.............?!?!!
Nothing personal at all of course but I see some pretty serious error there.