If/When they are boring the cylinders it's a good idea to use a torque plate. Basically it's a metal plate with holes knocked out for the cylinders that gets mounted and torqued to the block (via the head studs) in the same fashion that the cylinder head would. Once mounted and torqued then the boring of the cylinders begins.

This takes into account any flex that the block/cylinders might have and will create more perfectly round bores.