I have a friend who rebuilds motors for a living. He uses name brand parts and his 350s are about $1,400 with an exchange. More if he has to replace the heads or other components. The work is done right. He sells to individuals and to shops. And he offers some performance options, like cams, compression, at reasonable cost.

Most mechanics will not use Autozone or other discount rebuilt motors because even if they come with a replacement warranty, they still have to stand behind the installation. So, they prefer to pay a little more and go with a trusted rebuilder.

The Autozone price is based on exchanging a rebuildable core. If you don't turn in a core, or if your core is not rebuildable, you pay more. I think you have to pay the core charge up front and you won't get your deposit back in full or in part until your core has been taken apart and inspected. This is a common practice. When your motor is rebuilt locally you know in a few days. When your motor is trucked to an out of country location it can take longer.

The base GM crate motor is a slug. Plan on swapping out the cam if you want some zip. Or upgrading to a higher rated and more expensive motor.

Look in your phone book or ask around. See if you can find a local rebuilder with a good reputation.