I've been where you have before with a 1978 Elky, I tried going from 2.41 to 4.10 with the stock carrier and it didn't work, the carrier would go in crooked and couldn't even shim the thing.
I have a new theroy about rear ends (they are such a pain in the ***, shim, preload, all types of **** I don't understand), if you have a question hire a shop to do it because you can't.
Good luck,
Eric