is THIS the restriction everyone is talking about?

[Fierofool]

That modification is good.  Leave the belly of the manifold alone.  Some have smoothed out the ribbing in it and found that it diminished performance.  Though they're very rough and crude looking, they help with the flow of air/fuel.  To take maximum advantage of your modification you'll need to bore the throttle body, maybe even add a spacer, too. 

The PCV port that goes into the snorkel must be outside the intake, else you have an open port with unmetered air being pulled into the intake. 

[f85gtron]

I was referencing the pcv hookup that goes between the bottom of the plenum to the pcv check valve on the rear valve cover. Can i shorten that one and connect it to the back of the plenum with the other two hookups, or will it have some kind of detrimental effect?
I won't mess with the inside of the plenum.  I can't get in there now anyways. The door is now closed....
Ron

[f85gtron]

Here's a shot of the exhaust port on the heads opened up. There used to be a hump on the back side of the spark plug hole inside the exhaust tunnel. It's now opened up and round.
I also gasket matched the middle and lower intake manifolds. The upper plenum didn't require much.
Ron

[f85gtron]

Here's the "y" pipe restriction taken care of! Here's a before and after.  That ought to just about cover it........unless I've missed something?
Ron

[Fierofool]

Are these extra parts you're working on or do you have your motor apart?  Surprising what a little bit of restriction can do against an engine. 

[f85gtron]

I've got the y pipe off currently. That's about it. All the other restrictions I removed when i did the top end overhaul......while i was in there.
Ron

[GTRS Fiero]

Now I know why your EGR is blocked off.

I know you have the 3.4, but does it breathe better?  I wonder how these modifications would've helped the 2.8, and why GM didn't do this.