Break-in fluids

Use a break in oil that's high in ZDDP (zinc). There are many good oils available, choose one you like.
Make sure you have the timing and carb dialed in as best you can before starting it.
Make sure you have adequate fuel and fuel pressure to keep it running for 20-30 minutes.
Make sure the cooling system is leak free and ready to go before starting it.
When you start the motor, do not let it idle, take it to about 3000 rpm for at least 2-3 minutes.
Then keep the rpm between 2000 and 3000 for at least 20 minutes.
Shut it off, and change the oil and filter.
After the first 500 miles, change the oil and filter again.