Sooo this one has me a bit puzzled... Foxbody 302 build, has maybe 5-7k miles on it. Re-ring frankenstein build, block I got out of the junkyard and rotating assembly I got from another fox motor. Everything was cleaned properly, crank polished by hand and on lathe, block dingle ball honed, all clearances checked (bout 1.5-2 thou on mains and rods).

Had a vibration develop at 4k plus RPM recently so stopped driving it and took it out. #5 main is toast, all the rods are fine though, none of the bearings look great but #5 is definitely the culprit. Usually with oil starvation a rod dies first so not sure what to think about this one, it clearly is a 50z crank and I had 50 oz weights on the flywheel and balancer... (SB fords have a 28oz and 50 oz external balance depending on year etc)

2 things that stick in my head:

1 - The starter bendix sticks for a couple seconds after starting then retracts... This actually started with the last motor (which blew up) I actually had drilled the starter holes out when I first put this motor together to get the bendix to return properly, just firing the bendix manually with a "lone wolf 3000" it would pop back immediately but when the motors rolling it takes a couple seconds... But perhaaaps it has been shoving the crank into the main during cranking...

2 - I had raced some audi looking mercedes a couple nights before the vibration developed... it was a deep freeway pull soooo it's possible the pan was sucked dry... that said it was full on oil, and I'm only spinning it to 6k on with a stock oil pump and pan... surely stock SBFs can handle 6k with a stock pan/pump right? It's always been my experience though that rod bearings die before mains sooo *shrug*