Conventional wisdom says roller rockers increase horsepower by reducing valvetrain friction—with the biggest benefits showing up at high RPM. But Engine Masters’ David Freiburger and Steve Dulcich are always willing to question conventional wisdom and will leave no horsepower sacred cow untouched. They’ve tested parts to see what really works, built engines to find the best power-building combination, and explored modifications like cylinder head porting to see if they’re really worth the effort. They do the hard work so you don’t have to.
In Episode 29, David and Steve rounded up a 372 cubic-inch small block Chevy that makes power through 7,000 RPM and put roller rocker conventional wisdom to the test. They tested a set of stock-style stamped steel rockers, stamped steel roller-tip rockers and full roller rockers, and secured them with Lunati polylocks instead of stock-style jam nuts. They even used a set of neato clear valve covers to show the rockers in action.
As is often the case, conventional wisdom is not so clear-cut.
To make things even more interesting, David and Steve tested a set of 1.5:1 and 1.6:1 ratio roller rockers to see if the extra lift was worth any power. You can see what they found by watching the test at:
Test 1: Howard’s Cams Stamped Steel Rockers, 1.5:1 Ratio, 7/16″ Stud
Test 2: Proform Stamped Steel Roller Tip Rocker Arms, 1.5:1 Ratio, 3/8″ Stud
Test 3: Scorpion Aluminum Full Roller Rocker Arms 1.5:1 Ratio, 7/16″ Stud
Test 4: Scorpion Aluminum Full Roller Rocker Arms, 1.6:1 Ratio, 7/16″ Stud
HRS-90007 Howards Cams Stamped Steel Long Slot Rocker Arms
PRO-66906B Proform Stamped Steel Roller Tip Rocker Arms
SCC-SCP1000 Scorpion Race Series Aluminum Roller Rockers, 1.5 Ratio
SCC-SCP1002 Scorpion Race Series Aluminum Roller Rockers, 1.6 Ratio
ARP-134-7104 ARP High Performance Rocker Arm Studs, 3/8″
ARP-200-7202 ARP Pro Series Rocker Arm Studs, 7/16″
LUN-84380-16 Lunati Polylock Rocker Arm Nuts, 3/8″
LUN-84716-16 Lunati Polylock Rocker Arm Nuts, 7/16″