Help Picking and Intake
Thread Starter
On The Tree
Joined: Feb 2011
Posts: 159
Likes: 0
From: San Marcos, TX/Greenville TX
Help Picking and Intake Alright guys -- I've researched this a bunch and am getting conflicting information. So I thought I'd throw it up here for opinions. Will an aftermarket intake make significant improvement over my L92 intake I have currently? If so, which one? I also currently have the stock 5.3 throttle body, so I could potentially keep my L92 intake and just upgrade the TB to whatever the L92 orifice is (~88 mm?). I use it to tow a trailer, so that's why the stall and cam may seem small.
The Truck:
The Truck:
- 2004 Silverado Z71 Crew Cab 1500
- 408 stroker
- LS3 heads
- Compression ~10.5:1
- Cam specs:
- Lobe Separation - 115.2
- Valve overlap - .5
- Intake
- Centerline - 113.2
- Duration - 226
- Lift - .61193
- Exhaust
- Centerline - 117.2
- Duration - 234.4
- Lift - .59533
- 4L80E transmission
- 2,400 stall
- Texas Speed stainless steel headers and full 3" exhaust
- Currently has L92 truck intake and the factory 5.3 throttle body
- Used for daily driver and pulling a trailer
Last edited by T-Top; Nov 26, 2020 at 11:50 AM. Reason: Corrected cam specs
TECH Enthusiast
Joined: Mar 2005
Posts: 663
Likes: 384
From: South Carolina
In Richard Holdener's youtube video "LS3 vs the world" intake test on a cam/headers LS3... the LY6 intake (same as L92 intake) made 577hp & 533ft/lb with a 92mm throttle body. The Fast intake with the long runners (length best for street) made 585hp & 534ft/lb with a 102mm throttle body.
For the cost of the FAST around $900 plus fuel rails it's not worth the 8hp & 1ft/lb of torque on the LS3. Your 408 will show more gains with the fast intake but with your mild camshaft choice... probably not enough to justify the price IMO. What does your research and the "conflicting information" show? I'm sure there are more knowledgeable stroker rec port members here than me.
For the cost of the FAST around $900 plus fuel rails it's not worth the 8hp & 1ft/lb of torque on the LS3. Your 408 will show more gains with the fast intake but with your mild camshaft choice... probably not enough to justify the price IMO. What does your research and the "conflicting information" show? I'm sure there are more knowledgeable stroker rec port members here than me.
Thread Starter
On The Tree
Joined: Feb 2011
Posts: 159
Likes: 0
From: San Marcos, TX/Greenville TX
Thanks so much RedXray. Richard Holdener's channel is actually one of the places I've been gathering info. His channel is awesome. I do wonder how much difference the displacement difference would make, since I think that test was a stock bore LS3. My displacement is about 11.5% larger than the stock 6.0, so I guess (585 - 577) * 111.5% = 9 horsepower may be the lower end of the potential gain, since I don't think it's necessarily linear. Hell, even if it's double that, at 18 horsepower I'm not sure it's worth the $1,000+ to go with the Fast. Especially since this motor particularly is supposed to make power down low for towing, and Richard Holdener's test showed a gain of only 1 ft./lb.
On the other hand, my tuner is telling me, based on what he's seeing with AFR etc., the truck needs the biggest intake and TB I can get. I'm considering just throwing a 92MM TB on it and seeing what he thinks after that.
On the other hand, my tuner is telling me, based on what he's seeing with AFR etc., the truck needs the biggest intake and TB I can get. I'm considering just throwing a 92MM TB on it and seeing what he thinks after that.
