After looking at your combination the heads in that camshaft the LD 340 would yield more usable power where you'll be driving. It'll also get better mileage. What do the heads flow? Is that LD manifold has been portmatched and cleaned up a little bit here and there like the divider and a few inches into the runners it's more than capable of taking you into the 7000 RPMs and making plenty of power. Those things are known to flow decent ootb, 240s or so as cast by themselves. Little work to flow 270's