1966 Casting number question

I'm looking at a 66 Roadster, 427/390, but the casting number is 3839912. Can't seem to match this to the car. Any ideas?

[Rob]

Sean,

I can't find any reference to that block number. I've looked here: http://www.mortec.com/bbc.htm and Corvette books. The only casting numbers that I can find that come close to the one you provide for a 427ci is 3869942, 3855961, 3855962, 3869942. Are the numbers clearly legible on the block?

[Tom Bryant]

Sean,
I came up blank too. Can you take another look at the engine. Sometimes the numbers are poorly cast and sometimes one digit will just plain be wrong...a mistake. I would guess it to be the 3869942 casting unless it is an obscure truck number or something.

Welcome to the forums.
Tom