Where to start.........Oh yeah, why the engine came apart to begin with. During the last 50-100 miles I put on in fall of '20, I noticed a little oil showing up in the radiator. No big deal, suck the oil off the top and top off the oil. Well, I also had at the same time a hairline crack at the drain plug bung on the oil pan. So, to fix it I decided to pull the pan and weld it up. After I removed the pan, I looked up and noticed a couple drips of water coming off the #4 main/cam bearing. Now the problem was going the other way.
So, out came the engine for repair....I also noticed the glyptal was questionable in the pan, so I just removed everything. Welded the crack in the pan and added a new drain plug/bung in the rear.
I sleeved the oil passage in the block on both sides and had my machine shop pressure test it with hot water-checked OK. So, more good news, my machinist was checking over the crank and magged it. Thought there was a hairline crack starting on #5 rod journal radius. I wasn't there to see the mag being done, but he does good work and I trust him. I can't see with my eye anything at all, so must be extremely faint. I dug out another spare 390 crank and decided, why not do the things I thought about last time.
I spent a couple minutes and removed all the glyptal inside and smoothed things out:
Here's the new(used) crank as it started after a pass from the magnaflux:
I decided to bull nose and knife edge the counter weights as well as remove all the rough casting. So I started hacking and grinding....
I figured since I was this far, I would take it to a semi-local place to have it cryogenically frozen. This crank was already .010/.010" and needed to go to .020" on mains and .030" on the rods to clean up. So this is what it looked like after it was frozen and machined:
I also had it REM polished. It's my poor boy billet crank.