Not long ago we ran an article looking at why the dirt track racing community has been slow to accept the LS engine platform. We learned that many classes and series make it more difficult by requiring all legal engines to have a distributor and use a single coil. There are some manufacturers and Sprint Car racing teams working to develop programs where the rules are less restrictive. If you are interested, you can see that article here.
But it looks like we missed a great example of an innovative engine builder working to see if they can find an advantage by utilizing the LS architecture.
Chad Carter and Chris Fletcher of Fletcher Made Horsepower (FMH) builds all types of engines, but specialize in developing engines for Sports Car racing and Circle Track competition. Carter contacted us shortly after our first LS article and we had some great conversations about their efforts to develop an LS engine for Dirt Late Model racing.
Of the different versions of the LS engine, the LS7 is capable of the most performance, so Carter says it was the obvious choice for the foundation of the program. FMH works closely with Bob Williams at All Pro Cylinder Heads for cylinder head and intake manifold development, and Carter says Williams has one of the best LS7-style race head designs available anywhere. The problem was there simply wasn’t a viable intake manifold casting on the planet at the time of their initial design.
So Williams set about creating a high-flow, single plane intake for the LS7-style heads by cutting up, welding and re-machining several different intakes. “That first intake cost us $3,500, but it worked well. It was the only one we had, so I moved it from engine to engine for a long time during the development phase in the beginning,” Carter says. “Since then we have had several, finally ending up with an All-Pro casting we feel matches the needs for the program.”
Carter also says he learned some lessons the hard way. For example, to remain legal under the common Dirt Late Model rules requiring a distributor and a single coil, Carter had to swap out the individual coil ignition system native to the LS engines, for a package that places a distributor at the front of the engine along with a single coil. The initial system FMH chose used an open timing belt which simply didn’t work. It would quickly become clogged with dirt, skip a tooth, and cause the engine to lose distributor phasing. So the crew at FMH designed and fabricated a distributor gear drive that is driven by the camshaft, totally enclosed inside a front cover to keep everything sealed up. The original pieces were all cut from billet aluminum, but to keep the engine more affordable, Carter says the LS Front Covers are now cast aluminum. “We focused on space, weight, and tolerances in designing the front cover to keep the unit as compact as possible in combination with the bottom mandrel and water pump,” he explains.
Currently, Carter says he believes he has worked through most of the growing pains developing his LS-based package for Super Dirt Late Model racing. We believe he is working with a few high-end race teams but can understand why he is hesitant to disclose that before unveiling the newest version in competition.
But he was willing to be quite specific with the build details. Along with the All Pro LS7-style cylinder heads, Carter says Williams is now able to provide more affordable intake manifolds, and valve covers to go along with their lightened cylinder heads. “The block we first used was a Dart billet block, but in an effort to cut cost we are now able to use Dart’s unique LS Next cast aluminum design which cuts weight by removing the crank skirts along with other performance-enhancing characteristics,” he adds. “A Winberg center-counter weighted crankshaft, Lentz connecting rods, and CP Pistons originally completed the rotating assembly. We are now using other manufacturers as well such as Callies, Carrillo, and CP for our rotating assemblies.”
Originally, Carter said he used aluminum shaft-mount rocker arms, but they didn’t hold up as well as he liked, so FMH worked with Jesel to spec out a set of steel shaft-mount rocker arms to match the rest of the valve train. The gear drive timing set and front cover is FMH’s own design, and it will work with either an MSD or Crane Dual Optical Trigger distributor and a Stewart Water Pump. Although it wasn’t the case in the beginning, Carter says he’s done enough development work and refined the package to the point that the price is very competitive, if not slightly cheaper than, other Late Model engines on the market. Of course, just like any engine builder, the final tab is based on the options chosen and performance required.
For its standard Dirt Late Model package, the FMH Late Model engine has a 4.165-inch bore with 4.00-inch stroke and displaces 436 cubic inches. And from the pilot’s seat, Carter says the driver will notice the engine has an incredibly wide torque curve. “A lot of Late Model engines will have plenty of torque so they won’t have any problems jumping up off the corners,” Carter says, “but this LS7 just doesn’t quit. It just keeps pulling past the flag stand all the way into the next corner. That’s why we worked so hard to develop this LS engine package for Dirt Late Model racing and believe a lot of teams will find it can help them win many races.”
We can’t wait to see the FMH Dirt Late Model engine driven in anger, and will definitely report back to you when we have more information.