I'm planning to port plenum soon, remove egr walls, and clean up entry. I was also CONSIDERING removing divider wall between port openings to runners on plenum, and siameseing runners slightly where they meet plenum, gasket match, etc. I've seen photos where others have done it, it looks like it would offer better air-flow, and less restriction. I just read on a post where it was advised NOT to remove these dividers! Why? I'm confused, I know others have done this very thing. I'm wondering, before I remove these dividers, and it's too late, is there a reason not too:? Could it kill bottom end, cause undesirable turbulance, or what? I would think that this would only slightly enlarge plenum volume / area, and also would offer better airflow / less resistance of air into runners. Any comments good or bad would be welcomed. I want to do this project soon, but don't want to "over-do it". What do you think? Also, since I,m not touching the stock intake, would there be any advantage in siamesing the manifold end of the runners...where they meet the intake manifold:? I thought this might allow each cylinder to pull air slightly from the runner adjoinong it ? Make sense? Thanks, guys!

 

As one of the ones who has done the siamesing of the stock runners, i'd have to vote against it, unless you have a lot of spare time on your hands with nothing better to do. I went from a well ported set-up, the the barely siamesed stuff, and at the same time swapped from a 2.5" dynofrack exhaust to a 3" fromaster w/ improved dual cat Y. I picked up a total of a tenth and not even half a MPH between it all, and i would bet it all came from the improved Y of the new cat-back. (The air was about the same at the track, and IIRC my 60's were comparable too so it's an even comparison)

Time/frustration wise, you're better served to just do a nice radius at the runner entries. Siameseing the stock piece is a PITA and you have to be really careful not to break through.

If you want to see it, pics of my set-up are at http://rain.prohosting.com/imwhom/junk/inj