Free over 60s cam
We hear the whiners all the time: “Everybody runs those stupid LS engines. ” We’ll admit LS engines are less than visually inspiring; there’s a good reason these engines are popular. We added a mild Isky cam, valvesprings, and lifters and added 70 big ones. Our dyno victim started life as a 2002 LM7 5.3L motor (325 ci) and is among the most prevalent LS engines on the planet. Factory specs for this engine with its truck EFI is 285 hp and 325 lb-ft of torque, which is pretty good for essentially a small-bore (3.78 inch), long-stroke (3.62 inch) version of the traditional Chevy 327.
Show us another engine that will deliver 70 hp with a simple cam swap! Because we were crunched for time, we didn’t baseline our engine with an Edelbrock Performer RPM dual plane intake and 1-3/4-inch American Racing headers, but the guys at did with an identical 5.3L motor that made 315 hp and 325 lb-ft of torque.
Even better, the factory 5.3L motor makes peak torque at 4,400 but with the Edelbrock dual plane, headers, and a bigger cam, peak torque happened at 3,900 rpm!
This broadened the rpm spread between peak torque at 3,900 and peak horsepower at 6,100 to an amazing 2,200 rpm.
We decided to give Isky a shot at the cam specs for our little 5.3L.
Along with the EZ-Roll hydraulic roller bushing lifters is a matching set of beehive Isky valvesprings, retainers, locks, seat inserts, and a custom set of 0.080-inch wall thickness pushrods.The pushrod length for our engine ended up being 7.500-inch long to compensate for the height of the Isky lifters.Given the net lash design of the LS engine, a different height pushrod seat in the lifter demands a change in pushrod length to retain the proper lifter preload. Swapping parts was not difficult, but because we were going to change lifters, this is one place where LS engine heads have to be removed where the small-block Chevy does not.The cam will push the lifters up into the guides and hold the lifters up off the cam so that the cam can be easily removed.Because we were using the Isky lifters with built-in retainer bars, we removed the plastic lifter guides and once the cam was installed, the new lifters dropped right in place.