Those of you who have followed our engine challenge already know the 500ci big-blocks featured this year far exceeded our expectations in terms of raw power. Even more impressive is the fact that these engines made their big numbers running on Rockett Brand's 93-octane pump gas.

This month, we'll go inside the engines of Mopar Engines West and Speed-O-Motive that placed fifth and sixth, respectively, in our challenge. Both these engines represent powerful and durable combinations, though the building techniques were somewhat different. Mopar Engines West holds the record for the most power and torque-their engine screamed to more than 761 hp and 656 lb-ft of torque. The Speed-O-Motive entry was somewhat milder, making more than 716 hp, but then proceeded to set Comp's dyno record with the use of a ZEX 300hp, nitrous-oxide kit.

Mopar Engines West, Newark, Ca
Founded in 2001 by Richard Nedbal, Newark, California's Mopar Engines West has been catering to the Mopar community since its inception. Richard began racing in 1963 and quickly learned that Mopar power wins races. He's been a fanatic ever since. While working as an integrated circuit engineer designing electronic fuel-injection systems, Richard built engines as a hobby. After selling his software company, he decided the Mopar community needed an engine shop with "high-tech" capability so he started Mopar Engines West.

In 2005, Richard merged his company with experienced engine builder and machinist David Timmon's shop, forming one of the best Mopar engine shops in the country. David's experience, matched with Richard's high-tech computer work, means that no project is too complex for Mopar Engines West. Examples such as the 8-CNC fuel-injected stack wedge in the now famous GTX-R or the 300hp fuel-injected Slant Six that we covered in Mopar Muscle demonstrate these guys are on the cutting edge of technology.

The Bottom End
Utilizing a factory block as the foundation for their build, the crew at Mopar Engines West paid attention to every detail when machining and assembling the bottom end of their engine. An Eagle 4.15-inch stroke crankshaft and factory RB length Eagle H-beam rods were utilized with SRP flat-top pistons for a final compression ratio of 12:1 with pistons installed 0.050-inch in the hole. The pistons were coated by Calico with a friction-reducing coating on the skirts and a thermal-barrier coating on the tops. Knowing that proper oil control equals free power, engine builder David Timmons spent considerable time customizing the oil system of this engine. Oil was restricted to the top end of the engine, and the valley area was sealed to keep oil from draining back over the cam and rotating assembly. He also custom built a crank scraper to work in conjunction with the Milodon windage tray and oil pan. A single-line, external pickup was utilized to direct oil to the Melling pump, which was blueprinted and modified to reduce oil pressure. Obviously building this engine for maximum power, the team at Mopar Engines West chose a rather large, solid-roller camshaft custom ground by Comp Cams. With 1.6 ratio rockers, lift numbers were in the 0.830-inch range on both the intake and exhaust valves. Duration at 0.050-inch lift measures 276-degrees intake and 278-degrees exhaust with a lobe separation of 105 degrees.