I have a 1989 Amberjack with twin 5.7 I/Os in it and they both have Alpha one Gen 1s on them. While I had the lower unit part I noticed one drive has ribbed bellows and it is clamped from the Housing to the gimble ring on both sides. This seems obvious to me that is like that so it can stay connected and move back and forth. However on the other drive my exhaust bellow is just a oval piece of rubber clamped only on the housing. It looks like it could be clamped to the gimble ring but if it was then it could not move. I did see some exhaust bellows for sale and some do not have ribs in them so it can do the accordion thing. Here is a pic.