Any love for a 373 SB

I'm not sure what machine work you're talking about, and I understand how they used to turn down 360 cranks to a 340 main journal size not ideal. The rest is really straightforward bolt up stuff. And I would buy a crankshaft forged, I have no desire to move to a cast crank after running 340 forged especially with a four-speed car
The whole idea your talking about involves the cast 360 crank...the additional cost to turn that down, the pistons have to be machined on the tops and bottoms to clear the crank, ect ect. That's why I say a 360 is nearly as good, and cheaper, the 408 is also cheaper than your 373 recipe.... just one man's opinion.