Thread: **Overkill LS4 Intake Manifold Upgrade**

I'm very pleased to introduce the Shutter intake manifold upgrade for the LS4 platform, available from Overkill Motorsport.

shutter90mmpic.jpg

I am very pleased to be offering this for the LS4 Grand Prix GXP crowd, this is a first of its kind, a true bolt on intake manifold upgrade for the LS4 platform. The Shutter name is tribute to Nathan Shutt, who first did this manifold swap, and whom has partnered with Overkill to bring you these kits.


For those who are unaware, the LS4 is severely restricted in the intake manifold setup. Basically the LS4 has its intake manifold bolted on backwards, compared to a traditional rwd LS application. To make this work, to route around the existing oil pressure sensor location on the LS engine, GM simply pinched off the inlet of the LS4 manifold, cutting about a third of the 75mm port off on one side. Trying to adapt a regular LS car manifold in the LS4`s place is not a straight forward job, requiring fabrication to get around the oil pressure sensor, and the DoD valley plate in general.


Our kits are based on extensively modified GM truck manifolds, which improve horsepower and also torque significantly. They are extensively modified to fit the LS4 which give them a great cosmetic look, and come completely assembled with new billet fuel logs and all required connections, new fuel injectors, throttle body solutions, and intake vacuum connections for the PCV, EVAP and MAP sensor. The kits do not require removing or modifying the oil pressure sensor or the DoD valley plate, they are completely bolt on in a couple hours. Gains are anticipated at 30-50 horsepower, depending which manifold you choose and your other modifications. Tuning is required and of course available from Overkill Motorsport!


First kit is a 75mm manifold. This has the same inlet size as the LS1.LS6 and reuses the LS4 75mm throttle body with an aluminum adapter plate. Optional is a MAF sensor upgrade with a 4 inch inlet with matching intake tubing and cone filter to complete the intake system upgrade. This 75mm manifold kit comes in at $999 and we anticipate it being very popular due to its pricepoint versus power gains.


Second kit steps up to a 90mm inlet size, same as the LS2.LS3, which we match with a 90mm LS3 throttle body. The larger inlet will obviously flow more air, and is great to have if you have a camshaft upgrade for example, or if you just want to ensure you buy the best for your vehicle. Optional is a MAF sensor upgrade, this time a 4 inch LS7 card MAF upgrade, with wiring adapter, matching intake tube and cone filter. Pricing is $1549 for the 90mm manifold kit.


90mm kits are available now, 75mm kits are available Monday Aug 17 and will be posted on my website.

Go to www.ls4manifold.com to go right to the Shutter manifold page
Go to www.ls4tune.com to go to my LS4 tuning and product page, or www.overkilltune.com for my main website page.

We were supposed to dyno test on Nathan's GXP but then while prototyping the 90mm kit he lost his mind and built a turbo kit, so I'm still waiting for the opportunity to dyno a stock vs 75mm kit vs 90mm kit

Well, just send some to Missouri for me.

You know Brian wouldn't pass up the opportunity to see how that Overkill cam of yours works against these intakes, just to see the difference in that green car of his

If it works good I'll buy it, lol. I'm planning on a dyno trip before I install the spray anyways, and it's just a tune/downpipe car. I'd be more than happy to give this thing a shot, Will

^^ willing to get those dyno numbers eh?

Sent from my SCH-I545 using Tapatalk

Originally Posted by blueguy

Well, just send some to Missouri for me.

You know Brian wouldn't pass up the opportunity to see how that Overkill cam of yours works against these intakes, just to see the difference in that green car of his

If it works good I'll buy it, lol. I'm planning on a dyno trip before I install the spray anyways, and it's just a tune/downpipe car. I'd be more than happy to give this thing a shot, Will

If someone was willing to dyno a before and after, I'd offer to pay the dyno costs plus a discount on the kit. Tune/Downpipe is fine, my only request would be that I do the tuning, and the MAF upgrade would be a must.

Will, I sent you a PM.

On sale for Black Friday at a BIG discount

Link: http://www.getoverkilled.ca/blackfriday2015.html

$250 off the 75mm kit

$550 off the 90mm kit with only 2 available

Is it just me or are those just truck intakes that are smoothed and sold for 4x the price you could buy them new for off ebay?

No manifold is a direct plug and play. What's needed is any 05 and prior truck intake you can use the stock fuel rail if you can use the truck rail but you must grind out the alternator bracket.
smoothing of the top isn't mandatory depending on your preference. Keep in mind though your hood may or may not rub

A Tb adapter is needed from eBay and a retune.

Are the TBSS and NBSS intake that already run a 4 bolt throttle body too large or does something else get in the way?

Truck intake are the same from 99-07 so long as it's a NBS truck. The early 99-01's will have a EGR port on them though.

There not the same. All the 05 and prior are as diffrnt style then then 06 trucks and later the tbss styles are to big and run 50%of the runner into the power steering inlet. The only way to run one is to go electric power steering. Trust me I have tried lol. I do have both Styles. And and I'm ring the 05 SSR intake which has a 90mm inlet unlike the rest of older trucks 78mm inlet

Not to argue but I'd like to see how the 05 is different than the 06 or 07 if the truck is still a GEN 3 NBS style. If the knock sensors are still up top like the 06-07 NBS trucks are the manifolds are the same as the older ones.

TBSS and NBSS are the same intakes, the silverado/sierra/yukon/tahoe/suburban didn't get the NNBS intake until the body change in 2007.5. As you said won't fit and I understand that.

Not like it really matters for the 5~ horsepower or less either intakes would make over the standard truck manifold gains.

any updates?