what's a good break in point for a new motor?

[Mr 5 0]

For what it's worth: I drove my brand new '90 5.0 'normally' for 500 miles (changed the oil and filter @ 100 miles and again @ 500 miles) then finally took it to redline at just under 1000 miles.

I changed the oil again at 1000.

Still running strong at 118,000 miles with no noticable problems at all.

I've changed the oil and filter (conventional oil - Motorcraft filter) every 2000 miles which is a major factor in it's longevity, I'm sure.