Motor recommendation

First off, thanks for all the help you guys have given me. My car is running pretty good. Chances are, this will be the last car i will be building. I really like this one. my motor is a 71 hp440, 440 source heads, edelbrock dual quad intake and edelbrock 600 carbs. Automatic and 2.76 gears. I had 3.55s but the 2.76 are awesome for the street. I use my car for a daily driver type and it sees a lot of freeway miles.
For this year. I am going to build a new motor for her. The one in the car runs good. How ever. I want a new fresh one that will last me for years. The one I have was just up graded. This will be a street car and may never see the strip.
I am wondering. Do you think I should build my motor back to some what factory specs. Only with the 440 source heads and dual quad set up. or, build a 512 motor. I am not going to short cut any thing in the build. I plan on keeping the car. I know this will not be cheap either. So I would like to do it right. If I did a 512. I would start with a different block and would have my car running till close to the end of the build. I just don't know if the 512 would be street friendly.
Any suggestions on building a very strong street motor. It must run on pump gas too. I am going to start making a list of what I will need to get. And start getting parts in a few months.
Thanks again
This is for my 66 fury.
Author: Furios66