Forged steel or cast crank???

I just picked up a truck load of parts today, and need a tad bit of info.

There is a, what I believe, to be a forged steel crank that has the numbers 253245 in the throws on each end. When I tap the throws with a ratchet handles, it ring like a bell, not a thud like on my other cranks. The mains are 2.50" which tells me it's a 318 or 340 crank, I'm leaning 340 because there was a bunch of 340 parts in the pile, heads, exhaust manifolds and some other stuff.

Any insight would be mucho appreciated.