Originally Posted by 2000StreetRod
... There is a mismatch of 10.9mm (76.2-65.3) which may be enough to warrant an adapter (spacer with tapered port)....
Very good Dale, and those are good pictures and measurements. I agree that with a 5mm difference in radius, that's too much to expect to smooth out of a plastic entry.
The upper intake is the biggest restriction of these engines, and the hardest to improve. The later engines are a little better, but we are still stuck with the restrictive tight turns and small ports.
The TB bolts are fortunately rather long. You may be able to use them if you can make a thin adapter of about 3/8" or so in size. With the tight bends of the intake entry, there isn't anything to gain by having a really long entry to smooth the change from 65mm to 75mm. That EGR pipe is bigger than I remembered, and the air has to turn hard right there also.
You are making progress. But on second thought I would like to get a harder look at a later intake. It may or may not be worth it to think about swapping. I wonder if there are any decent pictures of 4.0's from late late Mustangs, besides the truck intakes. Regards,
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