[64fury]

Could there be a 1 infront of the 8 as a first number? If so then it could be: 1852029 that number was used twice once on the 413 from 1959-62 then on the 426 wedge from 1962-65 both are RB's The -3 at the end should indicate the year as 63' which would put your block as a 63' 426 Wedge*.

Interested in selling it? as it would go great in my 64' whose original engine was a 426 with the same casting numbers!

*At least according to the info have at hand! I could be wrong!