Quote Originally Posted by Northstar125 View Post
Yup. The series 1 3800 from 88-92 had aluminum intake manifolds.

I dont know why they ever even went to plastic? Probably saved them $1 per car...
Many manufacturers went to plastic. They offer better performance. Not only is the plastic lighter, but while unfinished aluminum castings are rough, it's easy to cast a smooth finish plastic manifold. Thus, the plastic manifolds always flow better than their aluminum companions.

When these were really catching among large manufacterers in the '90's, there was usually a good 15% increase in performance and economy from the plastic manifold alone.

On the Dex note, GM was increasingly notorious for intake manifold leaks as soon as they started using aluminum intake manifolds - WELL before the introduction of Dex.