Without really knowing why it is leaking, particularly given that you have retorqued the bolts twice, it’s had to say whether it was a defective head gasket, a block that is not true,a head that may not be just right. You could try some Barr’s head gasket fix if you did not want to redo the work. Me, I would probably pull the head and try a new gasket. You might also ask the machinest whether the head was magnafluxed for cracks. You might also ask him if the head was resurfaced when it was rebuilt. If not, I would do both when you pull the head.
