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LS Engine Cam Test Comparison - Ultimate LS Cam Test

Hands On

By Richard Holdener, Photography by Richard Holdener

Here is a common question among LS engine enthusiasts: My buddy, Joe, just bought a new cam for his 6.0L and wants to get rid of his factory LQ9 cam. Is that a good cam for the 5.3L in my truck, for my 240SX drift car, or the LS engine I am swapping into my second-gen Camaro? In this ultimate LS cam comparo, we've answered that question, and others like: How much is an LS1 cam worth over the 5.3L? Ditto for the LS2, LS3, LS6, LS7, and LS9. Is there any difference between the LR4, early LQ4, and LM7? Heck, we even threw in the L33 (aka H.O. 5.3L), LSA, and LQ9 cam just for good measure. We wrestled with valvesprings, cams sensors, and differing bolt patterns to get all these cams into the engine and on the pump. The result is a guide that will help you select the best OE GM cam for your 5.3L build. Why stock cams? These cams can be had for pennies on the dollar and benefit from millions of dollars spent on the research and development of idle quality, longevity, and fuel mileage. Why the 5.3L? It's the most common LS engine ever made.

The 5.3L used for testing was bone stock, which required at least a valvespring upgrade for the high-lift LS9 and LS7 cams. Even the LS2, LS3, and LS6 cams offered more lift than the factory 5.3L (LM7) springs could support, to say nothing of limiting rpm potential. The spring issue was easily cured using a beehive upgrade. Next issue on the list was the fact that the LS3 and LSA cams were single-bolt that required a front cover equipped to accept a front cam sensor. The LS2 also required a front cam sensor (no provision on the cam for rear sensor), but the LS1 and all other (early) three-bolt cams required a rear sensor. The three distinct cam families also required different timing (cam) gears and a management system that allowed such hybrid mixing of crank and cam sensors. Credit the Holley Dominator EFI system for the ability to accept and tune all of the different cam profiles.

While we were on factory cams, we decided that in addition to the peak power gains, it would be interesting to document things like idle vacuum, cranking compression, and average power and torque gains lower in the rev range. In addition to running the stock cams, we also decided to run a handful of aftermarket Crane cams. With its new offerings, we were excited about both the Direct-Fit line of cams that require no spring changes and a few of the smaller performance cams with similar duration to the factory options. We wanted to know how an aftermarket cam of equal (or near-equal) duration compared with the stock stuff. With that in mind, we ventured off to the dyno. Check out the results to see how your favorite cam compared with the factory LM7.

Baseline: 5.3L LM7 Cam

Being such a diminutive factory cam, it is not surprising that power fell off so rapidly past 5,500 rpm. Run on the high-mileage 5.3L, the stock 5.3L cam produced peak numbers of 353 hp at 5,200 rpm and 384 lb-ft of torque at 4,300 rpm. It is interesting to note that the same cam was used on the smaller LR4 4.8L, and that combination (same heads, cam, and intake) makes peak power 300 rpm higher. Obviously tuned for low-speed power, torque production with the stock cam exceeded 350 lb-ft from 2,700 rpm to 5,300 rpm. We tested the LR4 and LQ4 cams, but these produced identical power to the LM7.

Baseline Test LM7 (5.3L) Camshaft

Lift 0.466/0.457
Duration 190/191 degrees
LSA 116 degrees
Idle vacuum 22.5 in-Hg
Cranking compression 175 psi
Peak power 353 at 5,200 rpm
Peak torque 384 at 4,300 rpm
Average HP 286
Average TQ 353
HP/TQ gains (over LM7 cam) NA
2,500 NA
3,500 NA
4,500 NA
5,500 NA
6,500 NA

LS1 vs. LM7

Measured out at 6,500 rpm, the early LS1 cam offered 63 hp over the LM7 cam, but the results illustrate that the gains did not come without a trade-off. The LM7 cam offered more low-speed torque (by as much as 22 lb-ft) up to 4,400 rpm, but the LS1 cam pulled away there after. Such is the effect of extra duration, as the LM7 cam was designed to build torque in the 5.3L. The LS1 cam would certainly offer additional performance if you kept the revs above 4,000 rpm, but know that below that point there was a torque loss.

LS Engine Designation: LS1 ('98–'00)

Displacement 5.7L
Lift 0.496/0.496
Duration 202/210 degrees
LSA 116 degrees
Idle vacuum 21.8 inches Hg
Cranking compression 165 psi
Peak power 382 at 5,500 rpm
Peak torque 389 at 4,800 rpm
Average HP 295
Average TQ</td> 357
HP/TQ gains (over LM7 cam) at 2,500 -22 lb-ft
3,500 -11 lb-ft
4,500 0
5,500 +31 lb-ft (32 hp)
6,200 +45 lb-ft (53 hp)
6,500 51 lb-ft (63 hp)

LS2 vs. LM7

The odd thing about the LS2 test was that this was the only factory cam with which we experienced valve float. Unlike all the other cams, the LS2 did not rev cleanly to 6,500 rpm, so we limited the peak power difference to 6,200 rpm. The LS2 cam impressed with its power production, offering more than 400 hp (peak of 403 hp) and just less than 400 lb-ft (399 lb-ft). Despite a jump of 14 degrees in intake duration over the LM7 cam, the LS2 offered more than 21 inches of vacuum and lost out to the smaller cam only below 3,000 rpm.

Engine Designation: LS2

Displacement 6.0L
Lift 0.525/0.525
Duration 204/211 degrees
LSA 116 degrees
Idle vacuum 21.1 in-Hg
Cranking Compression 175 psi
Peak Power 403 at 6,100 rpm
Peak Torque 399 at 4,900 rpm
Average HP 305
Average TQ 370
HP/TQ Gains (Over LM7 cam) at 2,500 -18 lb-ft
3,500 0
4,500 0
5,500 +46 lb-ft (48 hp)
6,200 +67 lb-ft (78 hp)

By Richard Holdener
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I know this is an old article but the data you have for LS6 is wrong. That whole table is a copy of the LQ9 table, and is very low in cam specs and I predict its also low for the power output based on previous research. 

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