Small hole in block where sump bolts. The lip of the block is cracked off about 3 inches x 2 inches long it was on the bed of the dyno with an ARP2000 head of a bolt.
As the hole was turbo side it's hard to see and being 4x4 it's covered by the diff.
I can't confirm what went first. I can't blame rod failure or bolt failure at this time untill the engines out sumps off and cranks removed.
All I know is the all the vitals were fine, oil temp, prwssure ect.
It made a few good runs. No rattling no noises
Then ramping up on another run bang. About 4500rpm