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OK, I had some guys over for the holidays, and learned a bunch about port matching. And looking at a head I had lying on a bench, I can see a whole bunch of head that forms a flat wall blocking the air flow from the manifold to the intake ports.
Question to the other 2.2L engine builders out there, how much of that do I remove (up to a depth of 1" per GCR)? Do I go back straight from the head along the bottom edge of gasket?
Will I need to increase my carb jets to counteract the leaning out of the air-gas mix?
Planning on port matching on the engine I am going to rebuild this year.
Thanks, guys.
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Bill,
My only experience is with the TBI manifold. I actually cut a TBI manifold an inch or so from the flange that mounts to the head and bolted it to the head so I could see how the manifold ports line up to the head ports. They were very closely matched. I just removed the casting flash and smoothed it a little to the 1" inch limit (and probably didn't gain any HP).
Are the ports on the carb manifold that much bigger than the ports on the head? I'd always heard that the TBI manifold is more restrictive than the carb manifold and that would explain it.
Hopefully someone who knows more about this than I do will chime in.
Bob Clifton
#05 ITB Dodge Daytona
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Bob: Yes, the openings on the headers match the openings in the gasket. But the openings for the intake ports on the head are about 10-15% blocked on the bottom, straight across, solid. Not a flashing issue. I'll try and take some pictures tonight to illustrate.
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B) I tried to add pictures <_<
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Bill, different motor but same principles.
I had terribly misaligned ports on my Rover V8, and did the port matching myself. Yes, I just went in 1", matched and smoothed, although the literature on the intake side is you want some roughness (maybe do the last grinding with 120 grit) to help swirl the intake charge. Reverse is apparently true on the exaust side -- a polished finish is better. Flow bench showed a 9% gain from the work. As a result I did have to go up a step richness wise on my needles (my carbs are a bit different than yours in that needle size affects mixture in addition to jet size) and my exhaust temps are still not where I want them (1400 degress at sustained WOT).
For cars from the 80s with poor castings, manifold and head designs, I think a good gasket/port match is one the best areas of improvement you can see. Have it and have fun with it!
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