Just check the part number,

 

Try this: On my 2000 camaro which has an LS! manifold the part number is on the passenger side and in the center of the manifold just above the PCV hose that comes from the valve cover. I also have an LS6 manifold on my bench and the part number is on the drivers side, in the center, just below the fuel line cross over pipe.
You also can try this: look at your T.B, there's a silver coolant line coming from your T.B.fitting to the front of the driver's side head. From there it goes under the T.B. to the passenger side head. Look closely at at this line as it goes under the T.B. if it looks like it branches off to the rear under the manifold, then you have an LS! manifold. You should be able to see this silver pipe from either side underneath the T.B.
If and when you find the part number do a Google search for that number

 

You can look from the front of the intake, look under the throttle body at the bottom front edge of the manifold, it will be obvious whether it is flat or curved.

 

Part number from the passanger side of the manifold is #12556333

 

I think you have an LS1 manifold
Look here
http://www.google.com/search?q=%2312...ient=firefox-a

 

Underside of an LS6...



The LS1 has an X shaped support for the bolt holes...

 

Looks like its got the vette LS1 manifold.

Check this thread over!

https://ls1tech.com/forums/generatio...ls6-print.html

 

thanks for the replys guys. looks like its the LS1 vette manifold.


How much is this holding me back vs. the ls6 manifold?

see sig

 

About 10 to 15 horse...