Plenum---upper/lower plenum ??? Comments solicited !!

[cammerfe]

While looking at different threads, I've noticed the use of the above terms in regard to the V-8 on a regular basis. But different posters use the terms in different ways. What is upper-lower? Comments please---What do you mean?
KS

 

[LeaSr77]

I don't know what they mean by upper and lower but I have the V8 also and i'm about to have my valve cover gaskets replace this week. When I ordered the the VC gasket kit, I also ordered 8 new plenum gaskets. So I guess there are four at the top and four at the bottom of the engine. I was told that these could be used again if they are not in bad shape but I was like what the hell, might as well replace them with new ones while everything is taken apart.

 

[EMPIRELS]

the upper plenum is the alluminum peice between the TB and the plastic intake manifold (lower plenum)...atleast thats how i look at it

 

[97stscaddy]

I've noticed the use of the above terms in regard to the V-8 on a regular basis.

Those terms apply more to the V6 engine than the V8. The V6 intake is split up into two "halves". The first half is right up top (it might have some lettering or the engine size embossed into the aluminum) which the throttle body is connected to, and the other half is the intake manifold which directs the air into the ports on the cylinder heads. The upper half is called the Upper Plenum, and sometimes the lower half (the actual manifold) is referred to as a lower plenum.

When I ordered the the VC gasket kit, I also ordered 8 new plenum gaskets.

I dunno who told you to do that but you don't need them. You do not remove ANY intake parts except for the tube that goes to the air filter to change the VCGs on the V8.

 

[ILLS]

the upper plenum is the alluminum peice between the TB and the plastic intake manifold (lower plenum)...atleast thats how i look at it

There is not much of a true "upper" and "lower" plenum on these cars but if I had to narrow it down I would probably go with something like what Empire said.