47-55.1 bore spacing

[mick53]

Hi folks, first I have to give a retraction. I had stated that I was getting a 24 port 24 valve cross flow head for my 292. I was looking at an airplane head or something else. The head I'm actually getting is a 12 port 12 valve aluminum cross flow. On one of the "I'm smarter than anybody and your an idiot" forums it was stated that the bore spacing on the head would never work on an I6. Freaked out a little I called Ryan Falconer today and ask him. It's the same. In the process it accrued to me that the I6 and the SBC have the same bore spacing. Was this a product of the manufacturing and/or the casting process when they started producing the SBC?