When I take mine apart someday, I'll do a piston depth on it. It's the original 1968 std bore pistons in it, but I've had the heads cleaned up surface cut a couple of times. And I've sanding scrolled the cambers.
With the price of 340s there were not to many being sold let alone rebuilt around here for years so when you got one they were usually factory, and its pretty quick to do,all you need is one old 340 piston to get the pin height,I really enjoy the details more than the big stuff lol.