Slant 6 identification help.

http://www.earlycuda.org/tech/engines.htm

2806830 -> it's a 225 (RG family)

I'm not sure, but the 1381 may be the date it was cast - in the Mopar 10,000 day calendar.

1381 would be Day 1381 - Sunday, May 9, 1965

http://maxwedge.com/articles/10k.php