[PinHead]

Originally Posted by pwells18

My sales guy called to remind me...
-why 500 miles...??

This is an excerpt from the Chevrolet LT4 Performance Installation Manual about the oil priming and initial break-in procedure.
https://www.chevrolet.com/content/da...p-19332622.pdf

Start-up and Break-in Procedures

Use only engine oil licensed to the dexos1® specification of the proper SAE viscosity grade. AC Delco dexos1 Synthetic Blend is recommended. For track events or competitive driving, use Mobil 1® 15W-50 engine oil.

Safety first, if the vehicle is on the ground, be sure the park brake is set, the wheels are chocked and the car cannot fall into gear. Verify everything is installed properly and nothing was missed.

This engine assembly needs to be filled with oil. After installing the engine, ensure the crankcase has been filled with the appropriate motor oil to the recommended oil fill level on the dipstick.

This crate engine require a special oil meeting dexos1.

Also check and fill as required any other necessary fluids such as coolant, power steering fluid, etc.

The engine should be primed with oil before starting. Install an oil pressure gauge (there is a plugged port that can be used to mechanically measure oil pressure and used to force prime the system using Kent More J45299 priming tool, see Figure 9/10)

When possible, you should always allow the engine to warm up prior to driving. It is a good practice to allow the oil sump and water temperature to reach 180°F before towing heavy loads or performing hard acceleration runs.

The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.

Run five or six medium throttle (50%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear
.
Run two or three hard throttle (WOT 100%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear.

Change the oil and filter. Replace the oil per the specification in step 1, and replace the filter with a new PF64 AC Delco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.

Drive the next 500 miles (12 to 15 engine hours) under normal conditions. Do not run the engine at its maximum rated engine
speed.

Also, do not expose the engine to extended periods of high load.

Change the oil and filter. Again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.
END

I always wonder about the new cars that are being test driven.

I doubt the Dealer adheres to this break-in procedure from GM Engineering.