Stroke old 340 or new crate engine

As being that it's not my money, build a blown and stroked 340! Custom pistons with around-40CC's will keep the CR boost friendly.
Unless you go with a blown and stroked 360. Icon has a off the shelf piston (IC982) for the 408CI with a -34CC dish that will result in a boost friendly 8.6CR with 63CC heads.
You might be able to run a crate stroker with "high" CR and boost on E85.