Ok, here’s wrinkle in the LS world that we had no idea was coming and it is a BIG one. Mercury Racing, the people that make all the awesome boat engines pulled the wraps off of a new engine design that they are currently working on at SEMA 2014. This engine is a DOHC, four valve per cylinder V8 that is based on a GM LS series engine. The particular yellow example you are seeing below is built off of a 6.2L LS3 engine and it is 100% totally awesome. Mercury is working on the design and they have not yet embarked on performance and durability testing so repeated questions out power output were brushed off no matter how sneakily we asked them. One thing we did find out that gives us a little bit of an idea of the power potential of this beast is the fact that the heads move MORE than 400 CFM on the intake side. Unless we’re way out in left field, that means that naturally aspirated this thing could be making 900hp and with boost? Holy smokes.
In place of the camshaft in the block there is a dummy shaft that rides in the first two journals and stops. This is done for oil control we’re guessing. One of the things that was interesting to think about is the fact that you could run a really wild stroker crank in this engine because there’s no cam interference to worry about, right? The gilmer belt style cam drives will be tested and punished until they are refined enough to stand up to 500 hours of running. That’s one of the standards we heard the Mercury Marine guys reference a lot. 500 hours is a big deal for them in the marine world and it equates (roughly) to about 100,000 miles of land based use.
The heads are absolutely freaking awesome. On the exhaust side, while the ports are relocated dramatically they are spaced the same as a regular LS engine so normal headers bolt up to the mill. The engineers said that the Kooks headers you see on the engine here were ordered straight from the Summit racing catalog. The camshafts are specially made by Mercury and when we got into thinking about hot rodding the engine we were informed that there is a lot of time in the lobe design of those shafts and it would be hard to really get much more out of them without running into some geometry issues.
The heads are multi-pieces. The “valve cover” is a thick and flat plate. Below that is another removable plate that would allow the cams to be taken out without the bottom of the head to have to come off of the block. After you get to those bolts on the bottom of the head you’ll notice that they (obviously) have the same bolt pattern as standard issue LS heads. With regard to the block, the only thing they did was to add that stub shaft in the place of the traditional cam. The intake valves measure 1.669 inches and the exhaust valves measure 1.319 inches.
We can’t wait until we hear one run on a dyno!
SCROLL DOWN TO SEE THE MERCURY RACING “SMALL BLOCK FOUR VALVE” WHICH IS A DOHC, FOUR VALVE PER CYLINDER LS ENGINE –