For those of you who've replaced plenum gasket
 

I got an unexpected night off work so I'm gonna rip into my truck tonight and install the Hughes plenum kit. I have a question about where to apply the RTV. I know it's supposed to go on the ends of the block between the block and the manifold, but where else? And how much should be applied? Should there be any on the plenum gasket itself? Any info or pics would be great. Thanks.

You can use a few dabs of hi-tack adhesive (like 3M yellow or black) to help position the intake to head gaskets, but other than that they should be dry. For the rubber end gaskets, put some RTV in each corner where they mate with the intake gaskets and then run a narrow bead along the top and bottom edges. Don't use too much or it will ooze out when tighten the manifold.

Don't forget to use some threadlock stuff on the bolts.

Hey I've done that plenuim thing twice on my truck. The first time it lasted maybe sixty k, with OEM parts. Just recently I decided to go bigtime and use the Hughes after market "High Performance" stuff. It hasn't got more than 35 hundred miles on it and is doing the ole valve rattling thing again. If I were you, I think I'd just take the plenium to a welding shop and let them seal it up permanently. I can't see any reason that it wouldn't work. Has anyone else tried this. I plan on giveing it a shot when I do it next.

Just because it's pinging doesn't mean the plenum is blown again. There are a number of things that can cause this. How have you determined it's bad again?

I haven't confirmed that it is in fact the plenium gasket, but it sure sounds like it. It only does it under hard acceleration and quits as soon as you let off the gas. What kind of test should I do to confirm that it is in fact the gasket? Have any of you ever heard of welding up the bottom of the plenium? I figure this would eliminate this concern altogether.

Do you have a vacuum gauge? This is the official procedure to test for a plenum leak: http://dodgeram.info/tsb/2000/09-05-00.htm

If you take it to a shop, make sure they know how to properly weld aluminum...