Ive heard the ls2 intakes can be slightly ported and outflow the ls6. Anybody else heard this urban legend? If true it seems like a no brainer to go with the big mouthed ls2 intake.
Dyno graphs would be nice on these two.

 

Yes , there is a thread on this" LS2 intake porting " This company ports LS2 intakes

The information that has been provided is good. However, keep in mind that the comparison, above, is with an unported LS2 intake manifold. Many LS1 owners who are looking for improvement in performance, search for an LS6 intake manifold and see 5-10 rwhp gain simply by bolting it on. It's a good choice, but they are getting harder to find and prices are creeping higher.

Many say the LS2 intake manifold is a step backward from the LS1 and they are right if you consider simply the stock unported LS2 manifold. The reason for this is that the LS2 intake manifold switched to a new process that sonic welded three pieces together. The result is that where the pieces joined together they rarely butt together properly and there are ridges and bumps that disrupt airflow. However, porting the LS2 manifold smooths all of these transitions. Basic Porting of an LS2 manifold will generally get up to 5 rwhp better than the LS6. Our Radical porting of the LS2 manifold generally gains an additional 5 rwhp over the basic porting. For the difference between Basic and Radical porting, go to our web site at http://www.peakspeedshop.com

Another advantage to the LS2 intake manifold is that it allows you to step up to a 90mm throttle body from the LS1 78mm throttle body. The cost of the LS2 intake manifold is less than an LS6 manifold, however, that is offset by the additional cost of having to pick up the LS2 fuel rails, injectors and throttle body as well as the cost for porting. In the end, though, it is my opinion that you will have a better intake system than the LS6/78mm setup at about half the cost of a FAST setup.

Since you already have an LS2 intake manifold, you're a step ahead of the game. We charge $250 for Basic Porting and $370 for Radical Porting your intake manifold. Also, when we port your manifold, it is just $75 additional for us to port your throttle body at the same time.

 

I've been curious about the same thing and haven't been able to find much info on this. It's my understanding that the LS2 intake is a good design, but as stated above doesn't make good power because it is poorly constructed. If porting it can fix those problems then it should make good power. But there isn't much info to know if that's true or not.

 

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There's several thread regarding this. Yes, if ported properly, the LS2 intake can outflow an LS6 intake. Most guys go straight from an LS6 to a FAST. The bad reputation of an un-ported LS2 intake in conjunction with the excellence of the LS6 & FAST intake(s) is probably why most ignore playing around w/ LS2 intakes.

I've got 'em both...LS6 & LS2. Neither are stock & both flow similarly after porting & plenum inlet mod's to the LS6.