Alright well that sucks...now what...can I get the bellows on without removing the bell housing
Yes, but it's not easy (actually very difficult and fraught with the risk of damaging the new bellows in the process).
You're working on a 50+ year old machine that had a design life of 15-20 years max. The entire thing is going to fall into the 'not easy' category. There's a reason why most boat shops won't work on anything more than 20 years old (and some draw the line at 10 years)...
The easiest way to do this job is to drop something newer in. I understand that isn't always the most affordable option for some people. The price you pay for not being able to pay the price, is expensive and difficult repairs and maintenance. That's just the way it is.
That gives you 3 options.
1. Update to newer equipment.
2. Live with old equipment and accept the 'price' that entails.
3. Give up boating.
Chris............