First Engine Build - Advice Needed

WTF what kind of machine shop has the customer buy pistons before measuring the bores, fluxing and cleaning the block.
the same ones that have them buy bearings before measuring the crank.
I wouldn't let those 3 shops touch a briggs and Stratton.
but then again I wouldn't let most shops do my work.
A crate motor is your best bet. trust the warranty , not the bullshit shop and self proclaimed machinist.