Making up my mind for my build.

[robertisaar]

no, i am not finished with the store but I have sportsman and competition porting for both gasket types. Its such a pain in the ass to keep it all simple. The felpro set uses the larger gasket size in paper form, so I can't even say paper gaskets now.

GM considers the metal tabs on the plastic gasket to be sufficient. Midnightrider argues to the death that the felpro are junk and the metal tab gaskets are the best (GM Tech). So yes, an aftermarket company is needed to make things right for the rest of us non GM techs.

i've always been told the(GM) gaskets fail because they are paper and that the plastic/metal ones were the solution... guess somebody told me the story backwards

[SappySE107]

I am talking about the upper intake gasket that is paper.

[robertisaar]

so i'm confused now:

GM UIM Gasket: Plastic w/ metal tabs
Felpro UIM Gasket: Paper

is that right? and does the LIM follow the same pattern?

[stewartfn18]

GM uim gasket: paper
Felpro UIM gasket: paper

GM LIM gasket: plastic
Felpro LIM gasket: metal

[Crazy83519]

So with the 34/3500 head/lim, 3400 UIM hybrid am I tied into the "Sportsman" porting, or can I go with "competition?

[SappySE107]

There are 2 UIM gaskets...errr, 3 now. GM used the same 3400 gasket for the 3500. Their gasket set comes with a metall upper, which is the same size as the felpro paper upper that has a silicone ring on it. There is no reason to worry about the upper gasket material.

The lower is either plastic like stock, or metal from felpro.

I offer sportsman and competition for either upper gasket. The 3400 upper cannot be ported to the larger gasket size (by WOT-Tech).

[jp_grasshopper_007]

you got to be kidding me:
GM knew about this problem since the 90s yet they refused to fix them? an aftermarket company has to come up with stuff that actually lasts...

They did it on purpose so you would come back to the dealership and by parts. They did the same thing to the motor so many people here love......the 3800 lol.