I decided to decode my block before I send it out to have it checked. Checked on the archived Mortec
http://web.archive.org/web/200805180...ww.mortec.com/ and nastyz28.com. If anyone sees anything I am decoding wrong, let me know...but looks like it verifies as a correct engine for the truck.
Casting 3969854 means it's a 402 BB from 70-72. THe E4*71 shows the block itself was cast on May 4th, 1971. Can't read anything else on the block so not sure when it was assembled or where...but seems to fit a 72 model truck 402.