preignition hammers bearings but not that quick. Of course he's going to testify that it had to of been pinging/preigniton like crazy & you ignored it & that's an intangible that might not be able to be proven or disproven

No. Those excuses were poor at best... all of them. He should have been more than happy to follow up on his work. I would have wanted to see the fallout from the bearing spinning for sure. Spun bearings can cause some damage. The extent of what occured could have scored the crank. It irks me to think he didn't stand behind his work and tried to shirk it off on you... and then follows up with going back on his word and not being forthcoming with the damaged part. Especially damning is that his inclination to correct the problem was to simply replace the indivdual crank bearing without removing the crank?? I hate hearing about outfits and people like that.

At 8 degrees timing and what sounds to be a stock dist, there would be no problem whatsoever with any pre-ignition. If there were any, which I doubt, it would not have had any impact on your engine. In fact, until I read this thread, I had not heard that theory before. If it was bad enough you would have heard it and shut it down anyway. I doubt the 23 miles you put on it was very harsh.

My sentiment. Those 23 miles were the most "babied" twenty-three miles that one could put on a 50K restoration that was making a very unwanted noise. Question now is, can i advance the timing to 15 to 20 and can it damage my engine?? Everyone on this thread has said to at least "double" my timing and to recurce my dist. Is there a posible straight answer to this?

also, could my timing being set at 8degrees cause preignition to destry my bearings??

I wouldnt be worried about setting the timing. Id be pulling the pan to inspect the bearings. I then be at the courthouse fileing a lawsuit against the so called builder. Once I got my money back Id be taking it to a repuitable shop and have it completely torn down and totally inspected and cleaned. For 88.00 bucks that engine should be gold plated..
there should of not been anything in the cooling system if the engine was ran through a pressure wash after being baked. Those blocks come out of the baking machines just about spotless. Thats a 3 part processed. Bake, shot blased and then air blasted. The pressure wash ensures a very clean block..

An engine dry start without properly priming the oil system could cause the bearing to die.

Detonation likely isn't your culprit.

there was a fair bit of black accumulation in the coolant when we drained the rad.

8 degrees is fine. That being said, I tend to agree with the other poster. For the motors sake and your piece of mind it should be looked at thouroughly before you accept it as is from the previous outfit. Steps that pertain to integrity and quality seem to have been ignored or overlooked. For 8800 that thing should have been perfect in all aspects... from cleaning and mag'ing right on through all other phases. That experience planted a lot of negative mojo. Who knows what is going on with the bearing cap, journal on the one main... much less the other ones. That would haunt you every time you turned the key. You want to drive this car.. flog it from time to time. that is what it is for. You don't want to go through the remainder of the cars life wondering if the motor is going to take a powder on you again.