, i haven't posted in a while because i have been going hot and heavy on the chassis, suspension, drivleline, plumbing and mods on my C2-GS clone. just about finished with that and getting ready to start on the body.
piniongear, welcome to hotrodders. here's my take, (and i had no intentions of posting tonight):
as always, i totally agree with oldbogie.
what i see in your excellent pics in this thread is supreme shoddy workmanship.
1-from the main bearing pics it looks like you have a bent/warped crank
2-from the rod bearing pics it looks like you have bent rods or a disasterously machined crank
3-adding weld to the crank holes to balance is just wrong.
4-the engine seems to have been assembled with a bunch of machining debris left inside
5-the lifters in the pics are toast, and therefore the cam is toast.
6-think about where all that metal from all those worn parts is hiding in your engine.
7-think about all the wear on the parts you didn't inspect yet from all the metal circulating through the engine.
8-CNC NE + MST know their stuff, so if they don't agree, i will bow to their superior machine shop knoledge.
i hate to be the bearer of bad news, but toss that engine in the nearest trash can and buy another 350, they are cheap enough, you will be many $$$$ ahead and you will save yourself many future headaches.
i have thrown away many trashed engines in my time, sometimes it's just better and cheaper to start over...
EDIT: and i would never ever use 5W-30 in any engine, i have always used 20W-50 and have recently switched brands for the higher ZDDP content...