Hi,
No hands on experience with an Allison. But to drop a VW motor out of a car, you only need a few inches of clearance to slide the engine back.
On My Duchess, I accomplished that by cutting away some of the fiberglass on the rear valance (wasn’t much, and I followed the rough outline of the engine block. I have to remove the crank pulley before moving the engine, which by itself gains a couple inches of room. No clue if any of this will help on your Allison.
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica Roadster
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