Jim,
I did a Google search on "383 mopar intake manifold installation" and found that this is a very common question and problem. I'm going to post a link to one of the sites but it seems that typically just the metal pan is used, no other gaskets.
When I put mine on last time I Copper coated both sides of the metal pan where it contacted the heads and intake manifold. I used one set of the included fiber gaskets between the intake and the valley pan and nothing between the valley pan and the head. This seemed to work for me however I have no history on the engine, I don't know if the heads or block has been surfaced or how much.
The following is typical of what many of the searches produced however you may want to do a Google search and see some of the other comments:
http://www.forbbodiesonly.com/moparforum/archive/index.php/t-43521.htmlDennis C.
On Wednesday, January 15, 2014 8:25:39 PM UTC-7, JimJablonski wrote:
I am kind of surprised this is such a mystery. Perhaps it is just that I know I can be rather annoying when it comes to details, but this week I talked to Edelbrock, Hughes Engines, and traded emails with a Technical Consultant at Permatex (after reading Ricky's Hylomar thoughts). Well, I got three different and rather squishy answers. Maybe I am making too big a deal of this? I've sealed up Bowtie intakes in my sleep and never had an issue...