I did this mod today and it is definitively smoother at idle as well as throughout the rev range.
deQ: the manifold thread is M10 x 1.0 (the side with the copper crush washer on it), the the other side of the piece that the old EGR pipe screws onto has male threads that a 3/8" brass compression cap wil fit on (compression fittings have finer threads that match this, other 3/8" plumbing pieces like flare etc won't fit), this is what I had on it until I put on a reducer fitting which would then accept a fuel hose so I could see if Jerry's suggestion was going to work for me:
I bought copper crush washers at Napa and a 3/8" ID fuel hose and clamps. Hooked it all up and noticed immediate improvement in idle and overall smoothness through all gears and revs. Because the engine is smoother it runs "quieter" with less effort, especially when starting from a stop. Awesome suggestion Jerry.
Since I fortunately saved my EGR piece after removing it last year (now I know why I never throw any old parts out), I decided to remove the fuel hose and brass reducer and go ahead and cap the center fitting and reattach the original metal tube:
So now it is permanent. If your metal tube piece is long gone, the above fitting/fuel hose setup will be more than adequate. Worth a try by all means, my engine runs even better now.
can anyone identify which size and type of thread is in that holes of the manifold ???
is it a metric ? or other ?