440 source ductile adjustable rocker arms.

Remove and clean camshaft.

Put on new break in lube

Check to make sure solids

Lash about 16 and 18
or whatever the manufacturer of cam suggests

Mark top edge of all lifters (Whiteout or grease pen or whatever)

Spin engine over without starting several times for 15 seconds.

Be sure lifters are rotating on cam!

Run the engine for about 10 minutes at a time and let cool down completely (Seating Rings)

Be sure temp does not go over 150 (Heat guns are cheap at (Harbor Freight)

Vary RPM from 2000 to 3000 (If Auto put a small load on engine against converter.

Pull Valve Covers each cycle and be sure lifters are still rotating.

Everyone has their own routine on new engine breaking in = There are a thousand
ways to skin a cat this is simply mine.

This is mine =It is a pain but the new cam cores and lifters are really
poor materials.

My .02 = For Free
Your mileage may vary