I bought 1966 that was a 6 cyl the previous owner put new v-8 front suspenion in the car with 5 bolt drums and no rearend change. Can you change the axels out to 5 bolt and use existing housing? What best way change the front to disc and what most common car get these off of?
Do you mean that the existing rear end in your car is the 7.25" (or something like that) with a 4 bolt pattern? I'm not sure if anyone makes 5 lug axles/brake conversions for that rear end. If you have an 8", then your options are tons of options for you.
Let us know what you have and maybe someone can help you with the advice that you need.
-Edgar
The search button is your friend. Disc brake conversions have been covered plenty. Also, "best" is a relative term. You will hear all sorts of different opinions.