Chevrolet has brought out a new ground shaking monster motor for 2006 to power the 2006 ZO6 Corvette. The engine displaces 427.6 cubic inches (7008cc). The new ZO6 shares nothing with the big block 427 of old. It is instead a new punched out version of the LS2 small block and now pumps out over 500 HP. That's right! 500 HP! More then previous 427 or 454 big block engines. The power is rated as SAE net instead of gross HP as in the 60's when the prehistoric monster rat motors roamed the streets. 

The LS7 is the newest small block dubbed the Gen IV by GM. The Gen IV has been completely reworked to handle the larger displacement and power output. The new block has a 4.13 bore and stroke of 4.00 with a bore spacing of 4.4 inches. The Gen IV block uses thinner pressed in liners instead of cast iron liners of the older base LS2 engine.

The LS7 uses a forged steel crankshaft, forged steel main bearing caps and titanium rods along with forged pistons. But wait! it gets even better! There is an 8 quart dry sump oiling system and the LS7 427 redlines at 7000 RPM. Hmmm, smells like a race engine to me!!

Oh to get one of these under my right foot and go Porsche hunting in the foothills. I always did like the big bore weapons! But.. enough daydreaming, back to business for now.

The monster LS7 makes the big power using only 2 valves per cylinder so everything is optimized for max flow. There is a new low restriction air cleaner feeding a 3.5 inch throttle body.

The intake manifold is composite and feeds massive CNC machined intake and exhaust ports leading to 2.20 intake and 1.61 exhaust valves. The latter having sodium filled stems for superior high temp durability.  

The new heads utilize a 12 degree angle to the cylinder bores for better breathing via a more compact combustion chamber design. The old LS2 used a 15 degree angle. Valve lift for the new LS7 is a whopping 0.591 via 1.8:1 ratio rockers.

A compression ration that reminds us of the old rat motor days is used: 11.0:1. This helps extract maximum power and breathing and helps increase combustion efficiency. Exhaust is handled via hydro formed headers that feed two variable baffle mufflers via huge 3.0 inch exhaust pipes.

Variable baffle mufflers? That right, at low revs (below 3500 rpm) all exhaust gases pass through a single well muffled system. Punch it and a high vacuum bypass opens up allowing for an almost straight through shot right through to the back of the exhaust system. I can't wait to hear the music this system is sure to produce.

Maximum of 500 HP is reached at only 6200 rpm. Peak torque of 475 pound-feet is reached at 4800 revs. To give an idea of how good this motor really is, 385 pound-feet of torque is reached at only 1600 revs. This is the maximum pound-feet of torque the new BMW M5 musters at 6100 rpm.

Bimmer season is now open. Bag em quick while there is still good hunting. 

Power is transferred through a high capacity clutch and gear changes are made through an upgraded HD version of the corvette's rear mounted 6 speed transaxle. Included this year is a trans cooler incorporated into the radiator. The trans oil flows through a second heat exchanger to control the temperature of the differential lubricant before returning it to the transmission.