Hi DemkoG,
The best rear end for the Alpine is a Ford 8" from a 1974-1978 Mustang II. It has the same 4 x 4.25 wheel bolt pattern as your Alpine. It weighs just a bit more than the stock Alpine rear end and you will never hurt it with a Hot V6 or even a small block V8, since the Alpine is so light. The housing and axles will need to be shortened in order to get it to fit under the Alpine. There are many different gear sets, up to a 4.55. There are posi traction units that fit them. To build an 8" like this, will set you back about $1,000 to $1,500.
The Dana is pretty heavy and the parts for them are expensive. You wouldent be saving any money trying to use one, because of the money you´d need to end up with what you want.
There are some earlier 8" rear ends in other Ford vehicles, but they are different inside and do not share the same bolt pattern. You can use them, but be prepared to change the bolt pattern to match your Alpine´s.
Jose