Why would you spent $300-500 to port $100 jugs? If you insist on using those assemble the top end and leak test and squish test before you have them ported. Also make sure whoever ports them knows how to measure the port timing and chamfer the ports. The problem isn't with the jugs breaking, its that the quality control is so low. I've seen sets with large amounts of voids, uneven ports, head studs misaligned, uneven decks etc. To save $100 over buy used oem cylinders you're taking a big risk for a little gain. You aren't going to get anyone around here to tell you its a good idea.