New life for an old 340 (stock stroke)

Well I'm still paying off the block but as for crankshaft I dont have one so I'm looking who's a good source for one when I start the build in december. I have a 318 crankshaft but its cast out of a 69. I'm trying to keep the cylinder walls as thick as I can but I will admit I'm still debating on the build and everything on how I want to go about it
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Never knew they put cast cranks in 69 318s. Besides that what is wrong with a cast crank.

A 340 @ .020 is the same bore size as a 360 @ .060.