Undeniably the most famous of all non-lead changers was Alydar. Watch him along side of Affirmed and you'll see the difference. Trainer, fans, and bettors would sit praying for the lead change and the other gear that may have come with it, only to be disappointed time and again.
Another famous non-lead change winner was Arazi in the Breeders Cup at CD as a Juvenile.

If you have access to this years Wood Memorial, watch Eddington as he approaches the 1/8 pole and his awkward lead change.
That should help you see the difference.

The most important thing is that the horse travels on the turns with his left lead. Ideally, he should change to his right lead upon straightening for the stretch run.

I'll leave the rest to the smart guys.