Naturally aspirated track and drag racing cams to suit well modified engines. Suits engines with high compression, ported cylinder head and good intake and exhaust systems. Great with stroker kits and ITB intake. Rough idle on plenum style intake manifold. Large low lobe spec for strong mid-range power. VVL crossover around 6k rpm depending on engine. VVL will pull to around 10k rpm depending on engine. Kelford Cams recommend KVS10-BT valve spring kit. Primary lobe spec: Intake: 272°/10.2mm | Exhaust: 254°/10.2mm