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GMPP Truck Cams DeskDynos Help


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I'm installing a 2002 LM7(5.3 truck engine: rated 290 HP or so) GenIII engine and transmission in my 240. This will be a cruiser and long distance driver. R200, 3:31 or so rear gears, 205 x 75 x14 tires (Stock 280zxt wheels and tires.) Sanderson 1.5 primary block huggers. My design performance parameters started out as !00+ and sub 13 seconds in 1/4 mile. I'm confident I can do this with this combination and a reasonable cam. Money however is an issue. My knee jerk consideration was to pop in a 2002 LS6 cam and springs and be done with it. However, my brother (A lover of all things Ford Blue; a believer in the value of Desktop Dyno; and the builder of a street licensed and driveable 10.8 1/4 mile Falcon) just advised me that his Desktop dyno predicts that an LS1 cam will pull more average torque from 2000-4,500 than the Ls6. The cam specifications for the LS6 , ASA, and HOT cams are as follows:

204/218 .555/.551 117.5 LS6 "'02+ LS6" ;

219/228 .525/.525 112 LS6/918 "HOT Cam" ;

226/236 .525/.525 110 918/921 "ASA Cam"

 

LS1 cams are inexpensive and if I could meet my performance parameters with a LS1 cam, I'd do it. Can anyone out there confirm that an LS1 cam would produce more average torque from 2000 through 5000 rpm than the Ls6? Frankly, it just doesn't sound right.

 

Thanks.

 

g

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zgeezer,

First off let me state that I'm not a cam expert but I do have some thoughts.

 

Here are the specs for the stock 01-02 LS1 cam:

197/207 int/exh @ 0.05" duration 0.467" / 0.479" int/exh lift 116 LSA

 

Based on these values I would say that the LS1 cam will probably make more "average" torque in the RPM range you mentioned than the HOT Cam or the ASA cam but not the LS6 cam and will fall off sooner than all of them. The LSA (lobe separation angle) of the ASA and Hot cams are fairly tight which will tend to push the torque band up in the RPM range. The LS6 cam has much higher lift and a wider LSA which would make me think it will produce very good torque and also be able to sustain it higher into the RPM range.

 

Again let me state that I'm not a cam expert so take my statement for what it's worth "nothing".

 

Wheelman

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With the stock heads on the 5.3 you will be hard pressed to take advantage of the ASA or Hot cam (valves are too small). If you run a stock LS1 cam you can keep the stock springs and pushrods, but the LS6 cam will require new LS6 springs and a different length pushrod. Keep in mind that the 98 LS1 cam is a little hotter than the 99-00 and might meet your goals.

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Oh, by the way. I happen to have a 2000+ 5.3 truck Street and Performance wiring harness set up for an automatic that I want to get rid of. I needed a manual tranny harness and ended up letting Speartech make me one. I'll let it go for $200. PM me if your intrested.

 

I also have a stock 99 LS1 cam that I'll throw in with the harness.

 

Here's the factory specs according to JPR @ LS1tech.com

 

Stock 98-00 trans am cam

 

Duration@.050 198.86 intake 209.25 exhaust

Lift .498 intake .497 exhausts

LSA 119.45

 

Stock 01-02 trans am cam

 

Duration@.050 196.37 intake 208.72 exhaust

Lift .464 intake .479 exhausts

LSA 115.92

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