You’ve got $2050 so far, plus whatever you do for heads(and if you had brought them a complete motor there would be disassembly time on top of that).
Then if you wanted it back complete, more labor.
What would be a reasonable amount of time to assemble a complete 383?
Measure all the clearances, ring caps, degree the cam, etc, then add all the tin.
And of course, someone had to clean all the pieces that got reinstalled...... all billed at the shop hourly rate.
It adds up pretty quick when all the manual labor you’re doing is writing the check.