I had $6000 in parts and machining for a 454 (purchased for $700 and included) that was totally rebuilt. Sounds like we have (I had) the same project. When it was done I had a balanced and blueprinted motor with new pistons, completely rebuilt heads with new larger valves (781 heads), Comp hydraulic roller lifter cam and Edelbrock Air Gap intake. I built the motor myself but I don't think labor is a big cost there (maybe $600?). I swapped the oil pan from my 402 motor, added headers and a new carb and I was off.
I learned a few lessons ($) on my motor build that I did not include (would have been worth that $600), and in the end wondered about adding a bit more for a fully assembled crate motor. You might not need to spend so much on your motor if the bottom end is good. I had things magnafluxed and sized/balanced so that certainly added to the machine shop costs.
I really love driving it with the 5 speed. I doubt you would regret it.