what years was the plastic intake plenum used on the bonny,i'm considering buying one,but my parents '98 se had a plastic intake plenum,with only 80,000 on it,the plenum melted,the engine started chugging coolant,wouldn't run worth crap,took it to a radiator shop,cost over 800 till the morone'* finally found out what the real problem is,anyways,which years was it on,and can you interchange a newer or older design like a cast iron or aluminum one?

with the series one, i think that the 92'* were metal and 93-94 were plastic? Someone chime in on that one. All series 2 L36 engines 95+ use a plastic upper intake. But there is a L27 uppermanifold (off the series3) which is aluminum and will bolt up to the lower intake manifold on a L36 but the throttlebody needs an adaptor and i think there are some other things to make this work.

The Series 1 (L27) had a Metal manifold for half a year (1992).
Series 1 (L27) had plastic manifold from 1992.5-1994 There aren't any common issues with this one
Series 2 (L36) had a plastic manifold from 95-Current, these are the bad ones.
Series 2 (L36) should be ok after 2000, supposedly the design was modified.
Series 3 (L26) has a Metal Upper manifold.

Series III is a direct bolt in, except for a throttle adaptor. The 00+ designs are just starting to come around to the milage where the originals would fail, so the metal one isn't a bad idea. It'* also much easier to modify for performance, since it'* metal and not a composite plastic.

do the supercharges bonny'* have a different plenum or are they both the same?

Yes, they do! ...it'* a supercharger!

Translation:

Supercharged Bonnevilles don't have a plastic upper intake. The SC replaces it, and therefore it has no problems as the upper plastic plenums do.