340 piston question

Just picked up a 340 from the cousin of a friend. He did not know much about the motor as he received it in a trade. As far as I can decode it is as follows:
Block 2780930 date 6 30 70
Heads 3418915-G J heads
Intake 3512100 date 6 23 70

Pistons marked 030 and have 4 small half circle relief cuts in them

Here are my questions:
How can Identify the pistons in more detail (ie. comp ration/type)?

How can I tell if this is a forged or cast crank motor?

Did any of the J heads come with the bigger 2.02 valves?

The lower end looks real clean and looks like it was a recent rebuild before it was shelved. I would like to just freshen it up. Is the intake that I listed above worth using?. If not what type intake and what type and size carb should I run. I am looking for just a streetable motor to put into my 70 dart.

Are the J heads worth having cleaned up or should I look for something else.
Thanks for any help?