If you use the cheaper cast crank, the cost to internally ballance the rotating assembly with heavy metal, will end up costing as much as the better steel crank.
The crank in the link is cast and it also says it's for internal balance. Does that mean it is for internal but still has to have mallory? I'm not an engine builder so forgive me.
This is all just possibilities and anything that came to reality would be if the cost was negligible, say just couple hundred bucks over a performance re-build. Previous owner had the 340 rebuilt using the low compression pistons. I was going to do a simple rebuild with the same combo but just higher compression pistons and have the heads worked to similar numbers as above.
I've always thought the same as many when the 3.58 340/318 crank comes up. Just build a 360. I saw the crank on Summit and thought for $364 and not much any cost above a basic rebuild you get more more cubes! Didn't know internal balance cast cranks still need to be balanced.