Just south of downtown Los Angeles in the South Bay area of the county sits the city of Gardena, home to Custom Performance Racing Engines. Established in 2003, CPR Engines has set out to push the envelope on performance engines and bring the latest innovations in high performance engineering and technology to the consumer – building engines for anything from boats, and off-road trucks, to monster sand rails, dragsters, road racers, drift projects, and of course daily driven streetcars. You may even remember our naturally aspirated 682 horsepower Motown II project that we enlisted CPR Engines to build for us not too long ago.
We recently caught up with Martin Marinov, owner of Custom Performance Racing Engines, and he filled us in on their recent work with Edelbrock and Isky Cams which created a truly unique shop owned hydraulic roller LSX 468. Marinov’s plan is to eventually punish it in class racing at the drag strip and transfer what he learned over to his street builds and higher end off-road builds.
Our Motown block having the finishing touches put on by one of CPR Engines skilled techs.
Where The Inspiration Came From
“We have been working directly with Edelbrock on intake manifold design and testing for their LS-R cylinder heads,” says Marinov. “We have always loved the Pro-Port raw LS-R casting, but we noticed that not a whole lot of manufacturers offered parts for it. Since our involvement in the design and testing phase, Edelbrock now has the Super Victor series single plane intake manifold for the LS-R, both carbureted  and EFI , and also offers a consumer ready version of the heads that are already CNC milled and don’t require $10,000 in parts and shop labor before they will fit your block.”
“The main reason we were so interested in working with Edelbrock on this to begin with was because we do a lot of off-road engine builds, where the LS is beginning to emerge as a popular option for Trophy Truck and Class 1 racing,” states Marinov. “This is something that will allow the Trophy Truck guys to make between 800 and 1,000 horsepower, which is really where they need to be. It’s also another reason why we wanted to test out hydraulic rollers, those guys are really tough on parts so they need something low maintenance and reliable.”
“This specific build will be put to the test in the N/A 10.5 class with NMCA,” says Marinov. “We noticed that everybody that goes for a build like this always ends up with something strung out with crazy high spring tension and a solid roller cam. We’ve done countless hours of dyno testing comparing solid roller versus hydraulic roller on many different build variations, and while a solid roller setup is absolutely necessary for some applications, we took a step back and found that we could go hydraulic roller on this — so we decided to be different and take that approach because who doesn’t hate having to replace valve springs and adjust rocker arms all of the time?! Plus, the hydraulic roller also gives us a noticeable bump in torque under the curve [RPM outside of peak power].”
“Many people out there running this platform are using newer low lash solid roller cams on street or street/strip builds, and that’s all fine and dandy if you don’t mind unnecessarily spending an arm and a leg on valvetrain parts,” says Marinov. “To be honest, nine times out of ten it’s nothing more than clever solid roller marketing on the manufacturers end, and customers eat it up because almost everyone is fixated on only that peak number. It’s unfortunately the Holy Grail for many. If the only number you care about is whatever peak power is at 9,000 rpm, you’re really missing the big picture — do you not realize how much you’re actually giving up to get that?”
“The perfect example was a solid roller 441 LS we built using LS7 cylinder heads not too long ago,” Marinov states. “After we finished dyno testing that setup, we converted it to a hydraulic roller setup and ran it on the dyno again to compare. Using the same 7,400 rpm rev limiter, the hydraulic roller lost about 7 peak horsepower, but picked up nearly 140 lb-ft of torque around 4,500 rpm! We lost all of that down low torque with the solid roller camshaft because of the more aggressive lobe profile. If you’re not always leaving the line at 6,000 rpm and spending most of your time up there, it just doesn’t make much sense.
Starting with the bottom end — which Marinov says they overbuilt to be able to even handle a healthy shot of nitrous — the CPR team reached out to RHS for one of their LS race blocks made using A357-T6 aluminum, which takes advantage of a tall 9.750-inch deck height and a slight overbore to 4.185-inches; locked in-between the main bearings is a custom 4.250-inch stroke crankshaft from Winburg; the reciprocating mass is produced by a set of Callies Ultra I-beam steel connecting rods and stout CP-Carillo pistons. All of the machine work is even done in-house.
CPR Engines' Hydraulic Roller LS 468 Specs:
RHS LS tall deck block w/ a slight overbore to 4.185-inches
Winburg 4.250-inch stroke crankshaft
Callies Ultra I-beam steel connecting rods
CP-Carillo custom pistons w/ 14.5:1 compression ratio
Edelbrock LS-R cylinder heads Edelbrock Super Victor LS-R single plane intake manifold [Carbureted – 2823 / EFI -28235]
Isky custom grind 55mm roller camshaft
- CPR/Isky custom designed lifters
Jesel Pro Series “Mohawk Beam” shaft rockers
Dailey Engineering 5-stage dry sump
“Obviously we used the Edelbrock LS-R heads to encase the top end on this project, so pretty much all of the valvetrain components were designed around that — everything is lightweight,” explains Marinov.
“We’re using PAC springs with titanium valves, Jesel shaft rockers, and the lifters are a custom design that Isky helped us with, which we then worked closely with a local manufacturer to produce,” Marinov elaborates. “It is currently the only solid bushing hydraulic roller lifter out there that I’m aware of. The spring tension we’re running puts it on the cusp of being called a solid roller lifter, but we still have that hydraulic cushion — it is what would be considered a ‘short travel hydraulic roller lifter.’ Which we also see a lot of value in adopting to our Trophy Truck builds.”
With Edelbrock’s single plane EFI Super Victor LS-R intake manifold bolted on top of this 468 cubic inch hydraulic roller LSX, CPR Engines managed to crank out an impressive naturally aspirated 986.3 horsepower at 7,500 rpm and 725.9 lb-ft of torque at 6,800 rpm on Q16!
“If you look closely at the dyno video or photos you will notice that we’re actually using a bright red 3D printed version of the Super Victor LS-R intake.”
With Edelbrock’s Super Victor single plane manifold bolted on top this 468ci hydraulic roller LS produced a healthy 986.3 horsepower and 725.9 lb-ft of torque.
“Edelbrock also sent us over a 3D printed tunnel ram intake prototype to test out, and we had even better results! But because it is not something that is going to be commercially available anytime soon, we left it out of the dyno video,” says Marinov.
With the tunnel ram prototype strapped down, the LS was able to eclipse quad digits — making 1,006 horsepower at 7,400 rpm and 741.3 lb-ft of torque at 6,000 rpm. That’s a gain of 19.7 horsepower and 15.4 lb-ft of torque by just swapping intake manifolds.
With Edelbrock’s prototype tunnel ram intake (not commercially available) mounted on top the LS produced outstanding power for a hydraulic roller application!
Martin and the rest of the team at Custom Performance Racing Engines already have this LS dropped into a Fox Body Mustang and are ready to run it through its paces for the 2017 N/A 10.5 class in NMCA West. We’ll be watching this build closely to see how much of this work transfers over to their other builds.