The 3 liter aluminum upper ports are much larger than the SVT 2.5 uppers, they're oval with a split to two ports right before the lower. The plastic ones are oval all the way through. If Warmonger spoke of the SVT upper being larger, he mis-typed or something... The SVT lower and the 3 liter lower are very similar, but the upper on the 3 liters are no comparison...
As far as the manifold sitting higher, there's about an inch to tall of a difference, right in the area of the IAC valve on the 3 liter manifold and the EGR area on the 2.5 manifolds. Won't quite fit without a custom IAC on the 3 liter aluminum uppers or at least it will be real, real close so that engine movement would dent the hood. As an added bonus, the 3 liter uppers are a medium length runner design which can be ported by backyard mechanics with a die grinder.
I have not measured clearance on of the plastic 3 liter uppers.
