Before submitting our Coast High Performance-built 406 stroker to a round of high-rpm dyno testing, we installed a set of Comp Cams Pro Magnum hydraulic-roller lifters. They don't look any different from the regular High Energy lifters, but they're internally designed to perform at higher engine speeds. "The Pro Magnum lifter has less oil volume," Comp's Billy Godbold explained. "The valving and geometry are set up to handle high rpm." These lifters also have a low bleed-down rate and less plunger travel, which means they require a bit more attention when it comes to setting preload. They aren't, however, a cure-all. "They'll solve a lifter issue, not a valve issue," said Godbold. "The lifter was fine; the valve was bouncing." Indeed, Comp's regular-issue handled our 6,500-rpm abuse just fine. Looking to the long run, however, we went for the upgrade. Godbold endorsed our choice: "It's set up to be a very stout lifter. It's really good insurance."

To a certain extent, installing a stiffer valvespring improves valve control and reduces issues like valve bounce. On the other hand, stiffer valvesprings tend to be heavier, and weight is the enemy when it comes to high-performance valvetrains. Heavier springs are harder to control, and are harder on the rest of the valvetrain. Installing beehive valvesprings allowed us to have our cake and eat it too. Our springs had nearly identical seat and open-load figures, but the newfangled beehives weigh nearly half as much, and stayed in control where the traditional coils strayed.

Old Beehive Difference
Spring 114.2g 69.5g -44.7g
Retainer 15.7g 6.0g -9.7g
Total -54.4g
26918-16 Beehive valvesprings
4705-16 Spring seat for 26918 w/0.570-inch guide
788-16 Titanium retainers, 7-degree
648-16 Locks, 7-degree
4753 1.250-inch spring shim kit (if needed)
Displacement 406.0ci
Bore x Stroke 4.155 x 3.750
Rotating assembly Probe forged-steel crank and rods
Pistons Probe forged
Compression 11.1:1
Heads Dart Pro 1 CNC, 227cc
Chamber volume 66cc
Carburetor 825-cfm Mighty Demon
Camshaft Comp Cams hydraulic roller
Valve lift 0.562/0.580 inch, intake/exhaust
w/1.6 rockers 0.600/0.619, intake/exhaust
Duration at 0.050 248/254 degrees, intake/exhaust
Lobe separation 110 degrees