Summit Racing™ Pro SBC 4/7 Camshaft for Small Chevy: Changing Firing Order Means More Power

Summit Racing™ Pro SBC 4/7 Swap Camshafts for small block Chevy can add more horsepower. The hydraulic flat tappet camshafts have leading-edge lobes designed by one of the world’s best cam designers to meet our specific valve event and lift targets. A 4/7 swap camshaft changes the firing order from the traditional 1-8-4-3-6-5-7-2 sequence to 1-8-7-3-6-5-4-2. The adjacent-firing cylinders are now 4/2 instead of 5/7.

This has several benefits. The engine will run smoother thanks to reduced crankshaft loading. Moving the adjacent-firing cylinders closer to the water pump allows them to run cooler, which lets you increase timing a bit. Those cylinders are also closer to the timing chain, reducing camshaft twist front-to-back and the possibility of valve timing change errors. The 4/7 swap also moves induction pulses closer to the center of the intake manifold plenum, which can help equalize airflow distribution to all cylinders. The result is more midrange power plus a bit extra at the top end with no other engine modifications.

Made in the USA, Summit Racing Pro SBC 4/7 Swap Camshafts are available in eight configurations. The lobes are designed so they won’t ‘go flat’ if you use one of today’s low-zinc oils. The cam profiles are stable when used with 1.5 or 1.6 ratio rockers so you can run the ratio that works best with your valve spring setup. Just remember to change your spark plug routing to the new firing order and you’re good to go.

Camshaft Specifications
Stage 1
Ideal for daily drivers and tow vehicles. Works with stock gears and torque converter.
Duration @.050: 204°/212°
Lift: .420"/.428"
Lobe Separation: 110°
RPM Range: 750-5,250

Stage 2
Slight idle note with 327 CID and larger engines. Works with stock gears and torque converter.
Duration @.050: 218°/222°
Lift: .428"/.450"
Lobe Separation: 111°
RPM Range: 1,000-5,500

Stage 3
Steady idle lope with 327 CID and larger engines. 3.08:1-up gears recommended. Largest cam that works with stock torque converter.
Duration @.050: 218°/227°
Lift: .465"/.473"
Lobe Separation: 109°
RPM Range: 1,500-5,800

Stage 4
Steady idle lope with 327 CID and larger engines. 3.23:1-up gears and 2,500 RPM-up stall torque converter recommended.
Duration @.050: 228°/236°
Lift: .473"/.495"
Lobe Separation: 108°
RPM Range: 2,000-6,200

Stage 5
Stable, unsteady lope with 350 CID and larger engines. 3.55:1-up gears and 3,000 RPM-up stall torque converter recommended.
Duration @.050: 236°/242°
Lift: .496"/.510"
Lobe Separation: 108°
RPM Range: 2,200-6,400

Stage 6
Serious lope with 350 CID and larger engines. 3.73:1-up gears and 3,500 RPM-up stall torque converter recommended.
Duration @.050: 242°/248°
Lift: .510"/.518"
Lobe Separation: 108°
RPM Range: 2,600-6,600

Stage 7
Serious lope with 383 CID and larger engines. 3.73:1-up gears and 3,500 RPM-up stall torque converter recommended.
Duration @.050: 248°/256°
Lift: .518"/.525"
Lobe Separation: 108°
RPM Range: 3,000-7,000

Stage 8
Bracket race/dual purpose camshaft. Very serious lope with 383 CID and larger engines. 4.11:1-up gears and 3,800 RPM-up stall torque converter recommended.
Duration @.050: 252°/258°
Lift: .533"/.540"
Lobe Separation: 107°
RPM Range: 3,200-7,200

CHECK OUT SUMMIT RACING’S PRO SBC 4/7 SWAP CAMSHAFTS FOR SMALL BLOCK CHEVY