Re: What 'break-in' procedure did you use?
I was joking about the Bon Ami but there is actual history associated with its use.
This was the GM approved break-in by the dealers back in 1955 for the new v8. They had nigh nickel content in the first engine blocks (super hard) and a chrome vanadium piston ring and too fine a cross hatch hone pattern that was not productive in achieving a proper ring seal. The cure was to run the engines at a fast idle---1500 to 1800 or so and let the engine inhale (with the oil bath air cleaner off) the powder off of a tablespoonfull or so of the powder thru the two barrel carb into the engine. Took about 30 minutes or so. Then run the car hard on a test drive, warm the oil good and change it. Return to customer. Seems Chevy did not want their new high reving v-8 to get a bad rep from the start and had thrown a goodly amount of heavy duty parts into the engines from the get-go.....forged cranks, rods, chrome-vanadium rings, oil filters, good high tensile valve springs, etc. on their Ford beater. At 265 cu.in. and 165 horsepower rating, it was a world beater....and the rest is history.