Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec 3.0L / 2.5L Lower inlet manifolds

Question for you guys

Are the ports on the 3.0L lower inlet manifold the same size as the ports on the 2.5L SVT / ST200 lower inlet manifolds or are they bigger??

1998 SVT (and I assume ST200) used LIM with 32mm secondaries (compared to non SVT 31mm)
1999/2000 SVT uses LIM with 34mm secondaries which is a modified version of the 99 3L (same 34mm butterflies). Some 99+ non SVts (several Cougars) have been found to have the 34mm as well. Some say if you have the returnless fuel system only HOWEVER, I have a 99 with return style and have the 34mm...
2000+ 3L use "oval port" lower, completely different with no butteflies.

What size is the primary passage?

Originally posted by Dan Nixon:

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1998 SVT (and I assume ST200) used LIM with 32mm secondaries (compared to non SVT 31mm)
1999/2000 SVT uses LIM with 34mm secondaries which is a modified version of the 99 3L (same 34mm butterflies). Some 99+ non SVts (several Cougars) have been found to have the 34mm as well. Some say if you have the returnless fuel system only HOWEVER, I have a 99 with return style and have the 34mm...
2000+ 3L use "oval port" lower, completely different with no butteflies.

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IIRC, the acutal size for the 98 SVT's are 32 primaries with 33mm secondaries. The later models (which Terry is offering right now) have 34mm primaries with 35mm secondaries. SHOShop has and upgraded upper and lower, in which the lower has a 37mm secondary butterfly setup. The upper and lower are matched as well.

Normal - 30mm/31mm
98/98.5 SVT - 32mm/33mm (measure out at 31.5mm & 32.2-32.5mm)
99/00 SVT - 34/35mm (measure out at 33.5mm & 34.5-34.7mm)

Even the largest SVT head ports (99/00) are only 34-34.5mm so SHOShop's 37mm LIM by itself would be a detriment to performance as the head ports would literally cut into the airflow badly!

Now on a 3L that had the head ports opened up maybe? However with even the Dual Honed SVT upper measuring in at 30.5mm/31.8mm I don't see them making a big difference by themselves!

For reference - a worked, triple honed UIM measures in at 33mm/34.3mm.

I don't see how you could install the sho shop lower manifold without port matching. It's what I had done in my car. I think the LIM would cause a power loss over stock from the ridge that would be there.

Roger