You can take couple of different approaches with this. It sounds like the dealer is charging a hefty price for the replacement, go figure.
A few things to keep in mind. If you want warranty coverage for your new engine you'll need the engine installed by a shop that is recognized by the engine rebuilder as doing good work. Jasper Engines has a nationwide network of shops that they trust. I don't think they have the best prices though. Their selling point is quality engines and transmissions.
If you plan on doing the swap yourself, you can get the engine from anywhere, even a chain auto parts place. You are likely to get your best price from a place like AutoZone, Pep Boys, Advance Auto, etc. Ask who their supplier is and then check them out.
If it's important for you to keep all the correct numbers for the car, especially if it's a special series Corvette, you should get your engine rebuilt by a reputable machine shop. Ask them to recommend an installer. You should be able to get the motor rebuilt for around $2500. You can expect to pay $500-$1000 for installation.
I'd look for a machine shop that is known for doing racing engines. The quality standard is generally better than most rebuilders. Check around with the hotrodders.
Make sure the installer understands how to deal with and preserve vacuum hose routing. Anyone can replace an engine, but carelessness in handling the brittle plastic vacuum hoses can become a lot of trouble after the motor is in.
Carl M King
Classic Chevy man
33 years experience in classic/muscle cars. Classic Chevy from 55-72.