Hey guys I am working on a little science project. As far as I know when Chevy produced the LS6 they kept most of the intake the same but lowered the floor and modified the inlet of the port. As we all know the LS6 falls off at 6500-6700. What would one do to modify the LS6 to add alittle top end power?
slightly larger plenum?
Shorten the Runners by .75 - 1"?
Phillip

 

I don't know if this will help, but here are pictures of the inside of an LS1 and LS6 intake. Obviously the oily one is the LS1 intake. It really doesn't look too much different on the inside.

 

Looks like you could ports some of that extra casting flash?

 

Take a hole-saw to the bottom and cut around the three support columns. Then cut at a 45 degree angle the floor out so it can be plastic welded back in. Cut out the velocity stacks and reweld them a little closer to the intake port. Finally wetsand everything down to 1000 grit and pray all that work didn't actually hurt power

 

In looking at the inside of the intake, here are my thoughts.

Cut the top of the intake off and weld a piece of plastic in between the runners so it is like the floor of a tunnel ram. Build a bigger plenum up top, and re-mount the TB on your new raised manifold. Of course, I'd make it where I could take the top off and I'd smooth out the insides with a bit of epoxy and blend the transitions.

Of course, then it wouldn't clear the hood.

I guess we will see, since there is a new manifold coming out soon.

 

Here is what I am thinking....
1) cut goose neck
2) cut bottom of manifold off
3) shorten runners 1" and move radiused inlet
4) remove posts
5) smooth all casting
6) built Phenolic Resin Plenum extension
7) install
Phillip