Ok, here's an update on my LS6 intake manifold project. Been doing some work on it indoors this winter, waiting for spring to actually get in in the SS. I have included some pictures. I bought the following items used:
LS4 fuel rail with injectors
LS6 Intake manifold
Truck TB
LS4 DOD valley cover (not shown) I cut the Oil sender tower at an angle and had it welded to clear the LS6 intake neck)
Misc. parts, plumbing, wiring , hardware etc. gaskets (get real GM injector O rings only, the FelPro bottoms are too small!!)
I decided rather then try to bend the fuel rail to fit over the LS6 Intake (wasn't going well) I cut the interferring crossover piece out and replaced it with some brass fittings, and push lock nipples and hose ( good to 250 psi). I attached the brass to the stainless steel rails by soldering on the new pieces using stainless steel flux and good solder. Had to custom drill (1/2") the brass fittings that attach to the rail, easy. See the pictures.
I used a truck TB 78mm, it had a square opening in front of throttle plate that lead to the intake neck that we don't use, so I epoxied that up.
I drilled and tapped and attached some brass fittings on the TB for the PVC and brake booster vacuum line .
I soldered some fender washers to the fuel rail where it bolts to the manifold since the LS4 fuel rail mounting holes don't line up.
In the back, I removed the factory vacuum ports/MAP attachment adaptor by knocking it out from the inside with a long rod. I epoxied a large fender washer in the resulting hole. I will attach the factory MAP back here to the right and lower down to clear the Power steering pump.
I made an adapter wire harness for truck TB to plug into the LS4 wiring ( pins are just in different locations )
Now I plan to take it apart and paint the whole thing before it goes in. Probably red.

 

No offense man but I wouldn't put that manifold in my car with those brass fittings, they just create more places for failure if bending it was even a wise choice in the first place.

This looks well thought out and executed but I would fear leaks because that is fuel...and fuel on top of a hot engine is not good.

 

I agree with Nacho.

 

I am guessing you are both young, maybe too young to remember when all fuel went into engines from above through metal fittings into a carburator. Trust me when I say, these fitting will not ever fail, they will hold 100 times better then all the plastic fuel lines you find now in new cars. They are all carefully and tighly assembled with sealant, every joint is either sealed or soldered and will easily hold many times the pressure of our systems. You do realise that the black fuel line that attaches to your fuel rail is sealed with a single tiny rubber O ring, thats it, you think thats more secure and safer then solid brass?? Think again. I have no doubts about my set up.

 

Young? I'm 78 years old. lol, jk

 

I agree the brass fittings will work just fine. It will be nice to see a good intake on one of these cars. I know a customer of ours will be doing the same on his turbo car.

 

Thank you, you are obviously intelligent and good looking! lol

 

And I would be the old man here lol

 

nice, the brass fittings will work just fine, i have ran similar setups using nitrous in the past on my 2 srt -4s that i used to have. my question is how much of a difference is there between this manifold vs the stock ported stage 2 one.?

 

Well I am 56, I saw dirt being invented!!

 

I have to think there will be a fair difference between even a stock LS6 and a ported LS4 manifold simply because of the "D" restriction in the TB neck and small plenum of the LS4 which for the most part cannot be "Ported out". Obviously this will be more evident a difference the more other power adder mods are made, such as better exhaust, higher ratio rockers or bigger cam etc. I don't know if the LS6 manifold is considered more of a power adder or a restriction eliminator. Either way you look at it, it adds up to more power.

 

I think it looks slick! Nice work. I wish I had the time to do something like this. I'm just buying a ported intake and calling it a day. Unless you want to make these for us.... lol...

-Mike

 

Thanks, I just worked on it a couple of hours a week during the winter. About a hundred trips to hardware and pneumatic fitting stores looking at pieces, getting ideas and buying parts.. The only other things I am going to do to it is probably trim down those fender washers I soldered on to the LS4 fuel rail mounting tabs to match up to mounting posts on LS6 intake to make them look a little better and paint the whole thing. Duplicolor has a 2 part spray to make it look anodized red or blue, I am going with red for the manifold and blue for the fittings and TB. I also need to mount a MAP sensor to the rear of the manifold, hope to find another one cheap, I am trying to keep my original LS4 manifold assembly together and complete and untouched, in case I have to put it back on.

 

Good luck with it. I think it should have come from the factory like that to begin with. When it's done let us know how the gains feel. I am really curious. Keep up the good work.

-Mike

 

any update on this? Would you be willing to make one of these and sell it to me? Thanks

 

You're going to be happy you invested the time.

 

Thread revival..

I've noticed most of the LS6 intakes on ebay come with the fuel rails and injectors.
Can we just use the LS6 fuel rail with our LS4 injector?

 

It is my understanding from those that have tried to use the stock oem LS6 fuel rail that it will not fit on our engines. It interferes with the alternator. I just wish there was a way to simply bend our LS4 rail to fit well. Stainless steel does not take to bending well. I even had to use a special stainless steel flux to solder it to the brass fittings and steel fender washers. My only real concern is the push lock black rubber hose I got from the pnematic fittings store. The counter guy said it was ok to use with gasoline, but he didn't look real smart. It is Goodyear hose. I am going to take a small piece and put it in a jar of gas with a little fuel injector cleaner in it to see if it holds up. ( I use fuel injector cleaner several times a year)

 

I bent the ls4 fuel rails. And as far as a difference in the ported ls4 intake vs ls6. I had a stage 2 ported ls4 intake and when i moved to the ls6 intake i gained around 25hp at the wheels.

 

What did you do to swap the LS6 on there? Was there a thread I missed?

Thanks