Hi gang, I just bought a street rod with a chey engine. There are no numbers on the front of the block boss. The only one I can find is the casting (?) # on the rear of the block. That # is 330817. I was told by the seller it was a 400 ci. I had one parts guy tell me if it did not have a harmonic balancer it was a 400. It does have one. Can anyone help? THANKS!