was there a difference between the years in these peices??

 

Yes. It has to do w/ the cold start valve and the idle circuit. If you put later style runners on an earlier style plenum, it will not idle. (ask me how I know )

 

Let me guess, you tried it and cussed a lot?????

 

the 85-88 runners are the same, and there are 3 plenums, but I don't remember the year breaks. You can tell by the fins on top. The speed density plenums have fins that start further back than the MAF ones

 

hey you learn about from cussing at things!!

 

any type of marking or stamp in the metal that would make this easier to spot....

anyone have a picture detaling the difference??

 

I could go out and take some pics later, but Speed Density plenums have two tapped holes above the vacuum ports on the passenger side rear for mounting the MAP sensor. Also, the drivers side runners on S/D setup, does not have the little tube running from the plenum to the base (which was the idle circuit on previous runners)

 

Thirdgens have three different style of plenums.

1st 85-88 style-has an EGR passage and a cold start passage, large IAC port opening between throttle blades. Also have longer fins on the upper surface.

2nd 89 style-has an EGR passage and no cold start passage, no IAC opening, have shorter fins

3rd 90-92 style has an EGR pasaage, no cold start passage and has a MAP boss, No IAC opening , have shorter fins


Thirdgens have two different style of Rinners.

1st 85-88 style-Has coldstart injector hole and CSI air tube on drivers runner, passengers runner has EGR tube.

2nd 89-92 style-Drivers side has no coldstart injector hole or air tube, passengers side runner has EGR tube same as 85-88

Extreme

 

is that the only differences? thanks alot!

 

Those are the only differences but remember some can mix and match and others can't. Intakes and throttle bodies are also different.
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