im not too sure what the plenum is, but from what i understand they are the top / bottom pieces of the throttle body?

My brother has an 86 or 87 firebird. its broke , its getting sent to the junkyard so im stripping the hell out of it. it has 2.8 MPFI.. so i took off the throttle body and the fuel injectors. i have a 90 RS 3.1 MPFI .. my top plenum is all just plain. the one from my brothers firebird has a circle emblem up towards the top that says 2.8 multiport fuel injection.. i have 2 questions about this.

are the 2.8 and 3.1 top plenums the same size? im planning on grinding all the rough off the 2.8 so i can make it shine real nice. and i want to put that on my car.

second question is can i take out the 2.8 emblem thing? and maybe stick in something else ( Maybe weld it?) in the hole or is it permanently in there?

and im wanting to leave the bottom plenum in there so i dont have to take my motor apart...

if its not gonna work to easily then ill just clean it up a bit...

thanks

 

to the best of my knowledge the plenum sizes are the same between those two different model years. The reason yours is plain is because ur car has the 3.1L v6 which has no writing on the plenum while the 2.8L is badged. YOu can probably make it shiny if you'd like, and i don't think there'd be any problems with using your lower intake on the same setup with the 2.8L upper plenum. And you can remove that 2.8L sticker thingie, not sure how, but i've seen it done, then just put in anything that'll fit, or make it shiny too. Good luck.

 

sweet, thanks a bunch

 

In the whole scheme of things, it is as simple as you think it is.
BE CAREFUL with the 2.8 emblem part, tho.
Can you say when top cracks trying to remove the emblem?

 

mine didn't crack when I got the emblem off, of course I stillhave a spare top plenum also