My 572 has had a Fluid-Damper on for 300 passes at 7000 rpm. Bearings looked excellent on tear down. Don't know how much power it makes but it has been as quick as 9.02@151, 3350lbs
Doug

Don't just glance in there and "have a look". You better get the motor out, completely down it and have a VERY close look at the main webs. Nuts don't "just come off" main studs. And as I said earlier, I would be surprised if untorqued main studs would keep the nuts on for ONE burnout, much less a few passes. I hope not, but am betting on cracked block, broken crank, or both

The dampner is NOT the problem

Great job catching the oil pressure through the traps. I always tell myself at the beginning of each day to check the gauges at the top of every run. I never remember to look until I'm on the return road.

Well the ening is out and apart. I really want to find a crack or something wrong but I can't. I guess i'm going to bolt it back togeather and hope for the best.

My 395ci and my 416 both have a Fluidamper on them..
the 395 has had it on for years now.. turns 8100 each
pass.. Its apart right now.. it looks great.. I just had
the pan off the 416 yesterday and had the #5 main off of
it.. looked new still

Do they make a stretch gauge fixture for torquing ARP studs?

I remember an article in Hotrod years ago about them losing a rod in a SBC after the bolts came loose. They found the nuts in the pan. When they checked the stretch after torquing to factory specs they found the bolts weren't close to tight. It ran for a while too before it went boom.

Maybe that's what happened here. Partially/improperly torqued fastener held on for a while and then fell apart.

Kevin