The stock 327 heads could have come with 3 different intake valve diameters and 2 different exhaust valve diameters, along with 2 or 3 combustion chamber volumes. As long as he knows what he expects from the package he can/could choose the compression ratio based on piston and head specs. I built mine with a C.R. of 9.00:1 - 9.50:1 in mind. 350 block bored .030", flat top pistons with 2 valve reliefs, 74 c.c. heads, I chose heads with 1.91" intakes 'cuz I wasn't building a high RPM motor, the 2.02" valves can breath a little more at high RPM but your low RPM torque can suffer. So with those parts it comes out to just under 9.50:1 compression ratio. You could also use the 350 rods or the 400 rods but you have to make that decision along with the correct pistons. My block came out of a mid '70's truck-4 bolt, high tin and nickel in the cast iron, heads are from 1972, stock 5.7" truck rods. The block has to be relieved at the bottom of the bore in order for the rod bolt to clear due to the longer swing of the new crankshaft, it has just a tad over a 1/4" more stroke than the 350.
