A friend has a Nailhead in his garage he has had for years, but has no recollection of its origin. Based on the casting numbers for the heads, intake, exhaust and block it appears, as defined on Buicks.net, that it's a '56 322. They are all 116XXXXX, 117XXXXX numbers.

However, the serial numbers listed on the site with the casting numbers all begin with V, followed by all digits. The serial number we found on the block on the machined flat under the middle exhaust ports on the driver's side is IXXIXXX 6. I guess the 6 specifies a 60 series motor, but can anyone explain the IXXIXXX serial number versus the VXXXXXX serial number?

This is for curiosity more than anything, but if it is significant in the identification of the motor please include that in your response.

Thank you.

Rick