Originally posted by Bike2112:
... The interesting thing is the size of the lowers. They measure much closer to the larger returnless size...



I posted a month or so ago about the same thing. I checked my LIM after cleaning and got the following measurements:

Upper LIM Hole
Primary: 33.45mm
Secondary: 34.95mm
Difference: 1.50mm

Lower LIM Hole
Primary: 32.64mm
Secondary: 34.05mm
Difference: 1.41mm

*Measuring procedure: Two measurements that agreed per hole, at ~90 degree intervals. Averaged all six of each type of hole to arrive at the above numbers. Measured with digital calipers.

So yeah, I'm still curious about the existence -- or not -- of the larger LIM, as the replies I received from my previous post were inconclusive, IMHO. (No offense to anyone who replied to it. ) Does anyone else have actual measured data from their larger LIM to compare with these numbers?

Originally posted by Bike2112:
...First, I have an 98 EO SVT #580 something I think...
...Is it possible My car was assembled right when they were switching over to the 98.5 spec...



My car was built in May of 1997, so it was a very early model. If your car is #580, then it was built before mine, as mine is build #786. That would put it well before the 98.5 model year changeover.

Originally posted by Bike2112:
...I noticed the uppers were all about 2-3 mm smaller than the lowers on both the short and long runner ports...



Yeah, mine had an ugly difference in port size between the UIM/LIM as well. The LIM-to-head-port interface was pretty mismatched as well. Almost looked like the heads were skewed a degree or two from the centerline of the engine. Some port matching is definately in order there.

Marty

98 SVT, Black, No. 786, May 7, 1997. K&N, MSDS, Xcal2, Tint, Antennas, Big Gulp(R)-Sized Cupholder, Rear Dome Lt., Koni/Eibach, DMD, Pre-98 Sails, Brake Cooling Deflectors, Sidemarkers, Etc. 147K+ Miles "Get the Door - It's GrooveNerd!"