LS3 Corvette with 273lr Cam



A street cam with an LSA of 112 is not going idle all that good since it wont make very much vacuum at idle speed.
Why not select a cam with an LSA of around 115 or 116. It will make more vacuum, have better street manners and certainly make great power.
Here is a cam profile that I think will make lots of power, but will have a more pleasant idle (especially in an A6 car).
Comp Cams Intake Lobe:
LSL lobe family
grind # 13016
223 / .610"
Comp Cams Exhaust Lobe:
LXL lobe family
grind # 13159
230 / .609"
Specify an LSA of 116 and a ICL of 114 (that will give this cam 2 degrees of 'built-in' advance).
These cam specs will result in the cam having an overlap of -5.5 degrees, which will still maintain a reasonable amount of idle vacuum and good idle quality.
To maintain the correct hydraulic lifter preload with this cam, I would specify 7.425" pushrods. These rods are .025" (25 thousands) longer than stock.
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BTW, your OEM LS3 cam specs look like this:
Duration
204 / 211
Lift
.551” / .525”
LSA
117.5
ICL
114.5
Overlap
- 27.5
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Ordering a cam with specific Comp Cam lobe numbers, LSA and ICL is easy if you find the right company that will allow you to select the exact cam specs you want:
Take a look here: http://www.texas-speed.com/p-161-com...-camshaft.aspx


The cam profile I was talking about has -5.5 degrees of overlap.
Still a pretty big difference of 8.5 degrees.
I'm not saying a cam with an LSA of only 112 degrees won't idle, but I think it will be pretty choppy.
Just my opinion, but an LSA closer to the OEM spec of 117.5 will certainly be a little more street friendly (especially with an automatic transmission) without any real loss of overall power ... His 112 LSA cam may make a couple of more ponies at high RPM, but it will loose a few in the lower RPM range.
All I'm saying is using an LSA of 115-116 degrees sure makes for a less choppy idle and less problems for tuning the PCM / ECM down the road.
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What's your background to say make it a 116? He's not running nitrous of forced induction or trying to pass smog. Don't make it that wide of an LSA.
Beyond that OP I ran the 237/235 113+3 cam from comp in my LS2 with a L92 top end, it was tame.






