A picture of a fuel injector (above), a few facts and a lot of supposition is all we know about the fifth-generation small-block engine on its way from General Motors. It is expected to debut sometime shortly in the C7 Chevrolet Corvette and be rolled out with the next-generation full-size pickup trucks, but no one is exactly sure what it will be.
What we do know is that it will have a cast aluminum block, direct injection, variable valve timing, a higher compression ratio and 4.4-inch bore centers, flex-fuel capability and it will be more fuel efficient. From there, the site EngineLabs.com runs through the rest of the rumors and the odds of them becoming reality. In the "Sure Bet" column, EL figures a more aggressive system of Active Fuel Management will be introduced for even greater efficiencies.
A surprising prediction to which EL gives a 98-percent chance regards displacement: several outlets have talked of a "base" 5.5-liter model with 440 horsepower that mimicked the numbers of the 2010 Corvette Racing C6.R, but EL expects a 6.2-liter and 5.3-liter V8 and a 4.3-liter small block that it thinks could be a V6. Engineers have already said that the 5.5-liter (or 5.3-liter if EL is correct) will not go into the Corvette. The site also thinks the C7 will be introduced with at least 450 hp. Lower down in the 90th percentile odds are innovations like a raised camshaft tunnel, dry-sump oiling for performance variants and eAssist.
After that, things get rather cloudy. A concentric camshaft only gets even odds, there's just a 20-percent chance of three valves per cylinder, and a mere 10-percent chance of an active intake manifold. As for that "advanced combustion system" that we know is coming, EL wonders if it will be genuinely all new, or a new variation on the Otto cycle. Head on over to Engine Labs to get all the insight and their rationales.