GM’s LS engine has quickly gained a reputation as the ultimate power house and it seems as if everyone is transplanting these engines into everything. While you can buy a well built Crate engine, because of the LS engines potential it can be quite expensive. Lucky for us, GM saw that same potential in the LS engine family and used a variant of the engine for everything from sports cars to trucks. What that means for us engine builders is there are plenty to go around in the junkyards. The problem is that the variants used in the trucks do not sport the same clout from the factory as the LS1, LS6, LS2, or LS7, but that doesn’t mean they don’t have nearly the same potential. Picking up a cheap 4.8L from the local junkyard, the host of Speed Secrets Richard Holdener teams up with Comp Cams to demonstrate just how easy it is to hit your target horsepower goals with a junkyard LS engine.
To get a base line the 4.8L LM7 is first ran on the Dyno with the stock LR4 cam, stock heads and rockers. Configured without accessories and controlled with a Fast XFI management system, the LM7 produced 335 HP @ 5,200 RPM and 344 Lb-Ft of torque 4,900 RPM. While thats not too bad, its not exactly enough power for a hot rod, so out comes the rockers and pushrods. Then off with the water pump and the stock damper. Under the front cover, the team removes the timing gear and stock cam. The cam of choice, Comp XR265, is installed and the engine is reassembled and rushed back to the Dyno.
Now at 382 HP and 359 Lb-Ft of torque the gains out of this mild camshaft were impressive. While Richard went with a mild camshaft, the larger displacement LS engines like the 5.3L, 5.7L, or 6.0L will accept a wilder cam while keeping close to the same manors, or if you don’t mind pushing the power band higher in the RPM range of the 4.8L you could even pick a wilder cam for it. However, if your goal is to keep the power band down low, you could always turn to a power adder like this Zex wet EFI nitrous kit, to supplement for more peak power. By simply installing the fogger nozzle in the inlet tube and equipping it with 125 HP jetting you get an instant 500 HP. In the end the team has a junkyard 4.8L LS engine worth 501 HP and 533 Lb-Ft of torque proving that you don’t have to blow your budget on a Crate engine to have a powerful LS engine for your ride.
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