Modern rally cars fling themselves sideways around woodland courses with 400 turbocharged horsepower on tap. Today’s Indy cars make between 600 and 750 horsepower to go 230-plus mph at the 500. DTM touring cars from Germany top 600 ponies. And contemporary NASCAR racers churn out 750 horses and regularly touch 200 mph on superspeedways.
This is all context for Chevy announcing its ZZ632/1000 crate engine at SEMA, the annual automotive bacchanalia-infused trade show in Las Vegas. It’s all in the name: The engine displaces 632 cu.in. and makes 1,000 naturally aspirated horsepower (or 1004 horses, but when you’ve entered four-digit-horsepower territory, it’s probably okay to round a little). It also delivers 876 pound-feet of torque on pump gas. That’s more power than a NASCAR stocker or an Indy car has. All that in a box—and maybe between the wheel wells of your own car.
Other crate engines with 1,000 horsepower have been made available, but the ZZ632/1000 is all engine, no power-adder required. The block is shared with GM’s already-available 572-cu.in. crate engine, which includes four-bolt mains and a forged rotating assembly. For 632-cube duty, the block has been treated to a 0.040 overbore and was redesigned to fit connecting rods that are 0.375 inch longer. Those new rods are topped by pistons that, in conjunction with the new CNC-machined aluminum cylinder heads, squeeze the air-fuel mixture as 12.0:1 compression.
The RS-X Symmetrical Port heads were designed by Ron Sperry, one of his final jobs at GM after more than half a century of building hot street and racing engines for GM. Rather than the uneven port shapes of previous big-blocks, these heads feature symmetrical intake and exhaust ports so that no cylinder is “starved”; all eight chambers get an equal air/fuel mix. It’s a trick Sperry used on the Gen III small-block (i.e., the LS engines launched in the C5 Corvette). While not strictly new, it remains an effective power strategy.