Re: were too short for inliner use
He's referring to the distance from the drive pulley to the discharge port. If you position the Eaton so that its nose aligns with your stock belts, the discharge will be forward of the intake manifold center. If you examine the linked M112 (= 112 cubic inches per rotation) you'll see that the discharge window is heavily biased to the front of the rotor length. This area should be centered on the manifold (not the whole port length).
1. there are other nose lengths, which differ slightly between models and years
2. Magnuson makes alternate lengths, but $$$
3. an existing nose drive can be lengthened with a splice into the shaft and a spacer
4. a thick transition plate (like 3" or more) between the blower and manifold allows the charge to be directly backward as an "S" shape (rather than at an angle), but this is going to need some R&D
5. a jackshaft run off your existing belt set and have its driven pulley farther back to match the Eaton
Eatons can also be rotated 90° sideways to use sidedraft carbs such as SU, Weber, Carter YH etc.