Good question, I would imagine it should with the right parts? The older magazine 340 build people have quoted a few times here lately mentioned that replacing springs allowed the engine to pull cleanly to 6300 as opposed to 5600 (IIRC) with stock spec 340 springs. Power was the same, but it didn't nose over.
OP: does it just keel over above 5500 or just not pull as hard? Aarcuda called a good one...may be other things amiss...
