I can only share my small block experience, but I bucked most of what is written in this thread.
1) I filled the block AFTER it was machined... checking the bore before and after it didn't move hardly SQUAT...
2) I never ran an oil cooler until I put a diaper on the car. Before that it never had any issue on the street. But once I put the diaper on it, the heat had no where to escape from the pan.
Mine is filled up pretty high (well above the freeze plugs in the side of the block... on a small block you almost have no choice but to do this because they are so low.) I can put my finger through the deck and touch the top of the fill, so it's up pretty high.
I feel like with everything, there is a lot of people perpetuating old wives tales from things they've heard.
Worst case it MIGHT need an oil cooler.... and at the absolute worst it MIGHT need to have the hone touched up. Hardly reason to throw the block away and start over...
My fill ( pics) on a 408 small block. Lost about 2 gallons of coolant. Water temp never sees over 180. Oil temp ( no cooler and 8 qt pan using 7 qts of oil - Royal Purple full synthetic race oil) seems to line out at around 220. That is about 3/4 hour driving on the street in 75 degree ambient temp. I believe that number would climb in hotter weather and for a longer period of driving time. Guess on that part, but rest not an old wives tale. Had my block machined after the fill. Have no idea how much the bores distort with heat and wasn't a high priority with the build anyway. It was a race only build and trying to get a stock block to live at 700HP range was the goal.
