Standard Base Circle

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 1 - High Lift - Smooth idle, great for towing, very fuel efficient.
INT/EXH - Dur @ .050” Lift: 200°/209° RR: 1.5/1.5 Gross Lift: .474”/.495” LSA: 110° RPM: 1600 to 5500 Redline: 6000 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 1 - High Lift - Smooth idle, daily usage for near stock engines.
INT/EXH - Dur @ .050” Lift: 204°/213° RR: 1.5/1.5 Gross Lift: .484”/.505” LSA: 110° RPM: 1700 to 5600 Redline: 6100 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 2 - High Lift - Mild street performance, slight lope at idle. Headers & intake rec.
INT/EXH - Dur @ .050” Lift: 213°/221° RR: 1.5/1.5 Gross Lift: .505”/.525” LSA: 110° RPM: 2000 to 5750 Redline: 6250 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 2 - High Lift - Strong torque, good mid range power.
INT/EXH - Dur @ .050” Lift: 209°/217° RR: 1.5/1.5 Gross Lift: .495”/.514” LSA: 110° RPM: 1800 to 5700 Redline: 6200 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 2 - High Lift - Strong mid-range, good throttle response, 2000 stall recommended.
INT/EXH - Dur @ .050” Lift: 217°/225° RR: 1.5/1.5 Gross Lift: .514”/.535” LSA: 110° RPM: 2000 to 5750 Redline: 6250 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 2 - High Lift - Fair idle, moderate performance, good mid range HP (2000 stall).
INT/EXH - Dur @ .050” Lift: 221°/230° RR: 1.5/1.5 Gross Lift: .525”/.544” LSA: 110° RPM: 2100 to 5800 Redline: 6300 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 3 - High Lift - Noticeable idle, good mid-range, requires headers.
INT/EXH - Dur @ .050” Lift: 225°/232° RR: 1.5/1.5 Gross Lift: .535”/.550” LSA: 110° RPM: 2200 to 5850 Redline: 6350 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 3 - High Lift - Slight lope at idle, needs headers, 2500 stall recommended.
INT/EXH - Dur @ .050” Lift: 230°/236° RR: 1.5/1.5 Gross Lift: .544”/.555” LSA: 110° RPM: 2300 to 5900 Redline: 6400 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 3 - High Lift - Rough idle, aftermarket intake and headers a must.
INT/EXH - Dur @ .050” Lift: 232°/240° RR: 1.5/1.5 Gross Lift: .549”/.559” LSA: 110° RPM: 2400 to 5950 Redline: 6450 Learn More

Chevrolet - 262, 267, 283, 302, 305, 307, 327, 350 & 400
Performance level 4 - High Lift - Street/strip applications, rough idle, 2500 stall required.
INT/EXH - Dur @ .050” Lift: 236°/240° RR: 1.5/1.5 Gross Lift: .555”/.559” LSA: 110° RPM: 2400 to 6000 Redline: 6500 Learn More