If you are using the original crank, rods and heads it shouldn't be more than 4k, assembled long block, standard type rebuild with forged pistons. That should include a balanced rotating assembly and most all new parts.
Maybe, but the issue is that a really busy machine shop would rather use all new parts than rebuild stuff that is 50 years old. SCAT rods are $300 a set and they are ready to go out of the box. It can take most of a day to rebuild a set of factory rods and you might not be able to save them all. Then you're hunting down some replacement rods and nobody is getting paid.
Same thing with heads. Edelbrock heads are $1500 for a set. If the customer says they can't afford that and want their 906 heads rebuilt then you know you are in trouble. Depending on how hard the 906 heads have been treated over the years they might not be easy to fix. New seats, valves, guides, etc. and the bill is over $1500. Plus it takes a few days of labor to do all the work and some hassle cleaning parts and ordering stuff, etc. It is a lot easier to have Summit deliver some Edelbrock heads which you quickly double check to make sure they are in good shape and then bolt them on.
