What we all called the 5.0 for last 30 years. The old "4.9" was actaully labeled the 5.0. And the new Coyote 5.0 will cost you about $11K grand... and thats just for the engine, not including the wiring harness and computer and motor mount adaptor kit.
How much HP are you looking to go with? or is it you just want a different engine in there besides the 3.8?
Where are you shopping? The new 5.0 retails from FRPP for just over $6000, the 5.0 out of the Boss Mustang retails for $11,000.