Over the years, IH has made many changes in the intakes for the V-8 diesel intakes. As we all know, the IDI is the big "H" shape with the inlet in the center of the "H". This was designed for a N/A engine with an intake mounted air cleaner (The big round, carb'ed big block style assembly). When the 7.3PSD came along, it was turbocharged by design. The turbo is mounted toward the center of the V in the valley, with the "intake spider" with the plenums that bolt to each head, with a "pipe" connecting it to the turbo. Next was the 6.0 (What I am most familiar with) they changed the design again. This application was going to be turbocharged and innercooled by design. But now throw in the wrinkle of the EGR system to keep "Uncle Sam" happy. The intake is now "U" shaped. The bottom of the U is at the front of the engine (About where the IP Gear Tower is on an IDI), and each leg of the U laying along the top of the heads. The turbo is located to the passenger side rear of the top of the engine, can is clocked with the turbo laying passenger rear to driver front at and angle. The hot side is toward the passenger rear, with the up pipes coming in an inverted Y from the manifolds to the turbo. The cold side is clocked with the intake pointed at the drivers front, and the cold out toward the passenger front with the IC tubes connected. The out from the IC comes up from the lower drivers side of the core support to the in port of the intake manifold. This location has 2 ports, one on top (facing hood) that is the cold in from the IC, and one on the bottom (facing valley) that is the EGR In. The design of this intake, is the bottom of the U is the fattest part. Each leg tapers in from the base to the #7 and * cylinders. The intake is much narrower at the top of the U than at the base. I am sure this is to help keep the velocity up to the back cylinders.
I do think you are on to something, with the equal length intake tubes on the IDI, in a turbo app. Or if they are not the same length, have the size of the pipe change accordingly. When the front cylinders (#1 and 2) would be "short and fat" and the back cylinders (#7 and 8) if the inlet was in the front, would be "long and skinny" to keep the velocity up.........
I do think you are on to something, with the equal length intake tubes on the IDI, in a turbo app. Or if they are not the same length, have the size of the pipe change accordingly. When the front cylinders (#1 and 2) would be "short and fat" and the back cylinders (#7 and 8) if the inlet was in the front, would be "long and skinny" to keep the velocity up.........
School me 
