I think the parts list is around $20K at retail. The wildcard is the original standard bore 427 block. Those are super hard to find so that would be an expensive part to acquire.

Heads are $2500
EFI setup with computer, dual throttle bodies, ignition, etc. is $4000
Intake is $1000
Rotating assembly is $2500
Cam and lifters is $1000
Rocker arms and pushrods is $1500
Water pump, oil pan, damper, valve covers, air cleaner, etc. is $2000
Block is $2000+
Machine work, balancing, assembly, dyno labor, etc. is $2000
Dyno headers were $700 custom built
Probably some other stuff I'm forgetting......