Both of the vehicles which I have crankcase evacuation kits on, are almost entirely street-driven, with mufflers, (albeit Dynomax which are essentially glass-pack free flowing) and both draw substantial vacuum, even at Idle.

Though not as effective as a mechanical vacuum pump, they still reduce internal crankcase pressure. It doesn't hurt and surely helps.

Perhaps you can find someone nearby that has a kit installed. When you remove a breather (engine running) you can feel the vacuum.