Any ideas on this 340 block ?

sccachallenger said
Before I decided on the date I'd look at the front of the block under the cylinder head, drivers side.
And Rick Ehrenberg had an article in Mopar Action about checking out used blocks, the example he used was a 1977 340 block! Obviously Chrysler kept casting 340 blocks for replacement purposes after production ended.

Boats! Chrysler used 340's in their boats into the late 70's. I have a 77 340 Super Bee III motor. I think the OP's motor could be a 78 boat motor. Sure looks like a 78 to me.