[spedrace35]

Ok you LS1 owners I need some information from all of you! Well just to let you guys know I have a L98 based motor, and yes the means I am a third gen guy, so I am not very familiar with the LS1. Any ways the cam (after market cams) that I have and the cam for the LS1 are similar to mine but the operating range for the LS1 covers a broader rpm band. Here take a look:

My Cam (XR276HR) Comp Cams
Operating range: 1800 ? 5800
Advertised Duration: 276 in / 281 ex
Duration @ .05: 224 in / 230 ex
Lift with 1.5: .503 in / .510 ex (I?m not sure exactly what lift it would be with 1:6 rockers)
LSA: 112

LS1 Cam (XR269HR) Comp Cams
Operating range: 1300 - 6300
Advertised Duration: 269 in / 273 ex
Duration @ .05: 216 in / 220 ex
Lift with 1.7 rockers: .525 in / .532 ex
LSA: 114

One More LS1 cam(XR273HR) Comp Cam
Operating range: 1600-6600
Advertised Duration: 273 in / 277 ex
Duration @ .05: 220 in / 224 ex
Lift w/ 1:7 rockers: .530 in / .534 ex
LSA: 112


My question to you guys is why is the operating range so much greater?? I would love to put one of those cams or get a custom grind cam with the LS1 grind to get that performance range!!! But I don?t think I would see the same results. But can anyone of you guys tell me why it is so much different. I was thinking that the LS1 was based off the 350 block. Are the heads at the same angle, 23*, as the traditional Chevy blocks? I really can?t think of any other differences between the two 350 motors. Well if you guys know just let me know.

Thanks you guys

 

[revolutionary]

The ls1 runs a 15 degree head that flows a ton more air. They start making power at a lower rpm and the better flowing heads mean you wont run out of air until a higher rpm with the same given cam numbers. They have a more efficient chamber that allows them to run more compression for the same given octane. The computer seems more responsive to changes as well. Side note is the ls1 uses a 55mm cam core like the all out race early style sbc bowtie blocks. This allows the cams to be more agressive in their ramping.

 

[santa_rosa_lt1]

correct me if im wrong but with a 1:6 RR the lift would be .536 in/.544 ex

 

[spedrace35]

Hey thanks a lot, make a lot of sense!! Well I posted the same question on thirdgen.org and these are some of the answeres that I got.


The LS-1 is a totally different animal than a Gen 1 SBC. Stock the heads are great and they're incredible when properly ported. The base circle of the camshaft is larger, increasing valvetrain stability with higher lifts and high ratio rocker arms. So the valvetrain design is part of the reason for the difference, but not the only reason.

LS1 cam has the same journal size as a BBC. Thats about as close as you can compare anything in it to a SBC. LS1 is basically a fresh new design, nothing in common at all with older engines.

I believe the heads on the LS1 are 18 degrees versus the 23 degrees on the SBC for better flow. Like was stated above the LS1 basic design is much better than the SBC and so the flow will be greater resulting in a greater rpm range for a given cam.

The operating range listed is just to give the consumer some general information. The intake manifold has a great deal to do with operating range and peak power. A TPI vs. a MiniRam with the same cam. The TPI will still peak in the upper 4000 rpm range while the MiniRam will peak above 6000 rpm.

This info is about the same stuff you already said, just a little more info if anyone wants it!! Thanks a gain for the help!