LA 340 Intake Manifold

Since you're mentioning a height issue to the hood, figure that out first before wasting time on the pcv setup. Sometimes the accelerator pump of a Holley carb will contact the outside top of an M1 single plane intake runner if used without any spacer. Check that first. If the carb will not sit flat on the intake without a spacer then you can skip drilling holes for pcv stuff and get a different intake.

The performance of that intake will be fine on the street when everything is properly tuned. The operating range is the "sweet spot" and does not mean it won't drive or idle decent at lower speeds. That being said, I did notice a tiny reduction in idle quality on my 360 when I removed a chinese dual plane and installed an M1 single plane, both completely stock with no modifications.