I’m not sure I’d write off the OHV (or cam-in-block) engine just yet. OHV engines still dominate large displacement engines for offshore racing boats - probably the toughest environment any IC engine has ever powered through.

In terms of power-to-weight and power-to-volume ratios, forced induction OHV engines have never been equaled. Indeed, Chevy big block OHV engines dominated the Can-Am racing series, where HP levels typically exceeded 800 HP. The only OHC engine to beat the big Chevy / McLaren combo was the Porsche turbocharged flat-12, which, it should be noted, was air-cooled (like an aircraft engine). The fastest non-hybrid LeMans car in history is the Peugeot 906 which had a V-12 Diesel which redlined at 5000 rpm. High rpm capability in a race car engine is not a requirement, but it is a choice. It is necessity to make big power with small displacement.

The drive for a DOHC engine for Corvette is driven by the need for commonality with other GM products and the tremendous drive to improve the GM fleets fuel economy. The near universal approach to this drive is to use a turbocharged in-line 4 with displacements from 1.0 to 3.0 liters matched with a multi speed transmission (7 to 10 speeds). A V-8 derived from these engines is the best hope for a future sports car, but nobody should confuse this for a drive for better absolute performance. It’s not.

Yup - Mercury Racing came out with these OHC heads about 2-3 years ago. I think they wanted to go to four valves to get more power. The cams are driven by a chain off the cam-in-block like their smaller CB4 prototype.

I was referring to the previous generation of GM-based and Chrysler-based OHV V-8's that have dominated inboards and inboard-ourboards for years. There are literally thosands of these engines powering Cigarettes and Catamaran speedboats on Poker Runs from coast to coast.

The ohv engine is loved for its low cost high output...and small size.

the dohc twin turbo will be excellent for tuners to play with so that is a big plus if a bit expensive to purchase.

The tripower four has new thermal managment advancements that are quite impressive in creating a consistent power output.

those advances transferred to our v8 would be a major win for us.

i would imagine with the upcoming hot vee v8 thermal managment controls as described in the press release of the tri power turbo four are critical to consistent and impressive power levels ..

hopefully the LT1 derived c8 base powerplant will also beenefit from GM’s advancements in thermal management.

The block, crank and stroke are all new for a V-8 anyway. The stroke is actually not that long compared to the piston diameter. The (expensive) carryover parts are the heads and the turbos. Those are clearly applicable to a new V-8 since you could use one of these heads for each side.

If you went "square" on the stroke with the same piston size as this LB3, the displacement of the derived V-8 would be about 5.0L. Alternately if you go up in piston size and keep the stroke square, the piston would be about 3.75" in diameter for a 5.5L V-8. NOT THAT BIG A CHANGE !!

I drive a C4 ZR-1. 5.7L 540chp. Find out what a Vette feels like when u can wind it up thru 7k. In fact drive a modded DOHC LT5 to put a real grin on ur face. Find out what its like for the hp curve to stay flat at the top instead of dropping off a cliff like an anvil. That’s a Vette.

Ron,

That’s the kind of HP dropoff I see on my dyno sheets too. My HP peak is at about 6900 rpm. Torque peaks at 5300 @402lbft rear wheel.

Micheal, I respectfully disagree. First, head castings can easily be changed, Second, a 2.7L I-4 that makes over 300 HP and nearly 350 ft-lb of torque is a very high performance engine. Third, there are clearly many ways to put together a high performance V-8. In GM and Corvette past history, from the days of Ed Cole, the Corvette has always used a corporate engine - the five generations of the OHV small block V-8.

Unlike Ferrari and others, GM has never built an engine solely for the Corvette, with the exception of the Lotus / Mercury Marine LT5 which proves the rule that such an engine is clearly unaffordable. For GM to bring a new DOHC V-8 to the C8 Corvette, it HAS TO draw technologies, parts and assemblies from the engines GM plans to build in much larger numbers than ~30,000 a year. The most important thing about the LB3 is it's use in GM's future pickup trucks, insuring builds of over 150,000 units per year. That volume of production of pistons, turbos, cams, etc. is what will make a high performance DOHC V-8 both possible and affordable.