So I pretty much have rebuilt the engine with all fel-pro gaskets with the exception of the front and rear main seal and the supercharger gasket. Then I found this youtube video where the guy says to avoid plastic gaskets for the lower intake manifold because they tend to fail after 60k miles. On that note, which others do you guys recommend I replace? I want to try to avoid taking apart the entire motor again but if I must...

Thanks a lot

The only gaskets that are a problem are the LIM gaskets. Get the aluminum framed gaskets and you will be set.

Yup, what Dan said^

You can get the aluminum gaskets (AC Delco Part # 89017816) from the GM dealer, ZZP or Rock Auto.

The AC Delcos are great, I went with Fel-PRO'* for mine, you get a few extra things in the kit you already need unless you have it already, like RTV, thermostat gaskets, o-rings for lower part of fuel injectors, also o-rings that fit the coolant elbow, also a MAP sensor tip.

^^I just bought that kit from Rock Auto for the PA recently, along with a new upper plenum. Can't wait to get those plastic gaskets out of there!

Yeah those old nylon 6,6 gaskets were of poor design, you are smart to be replacing them and not risking possible leaking, and or engine hydra-locking in the future, IMO the 3800 II is too nice of a motor to let become ruined by that design flaw.

I couldn't agree more William, in fact I remember complaining to the GM dealer about them back in '04 when I was replacing them on the GP. They said I was lucky to be getting them in plastic, never mind aluminum. I replied that maybe when GM replaced enough engine bearings (as I was doing on the GP) that maybe they would offer them in aluminum.