'71 Duster 440 or 360? Pros and cons

Hmmm. I already have a "fun" street car. It's a '74 Nova with a 350. It gets 17 mpg and is a blast to drive. I am also in the process of building a '65 Mustang with a '95 5.0/5 speed. That car is getting painted right now. There really is no rush to get this Duster thrown together. I am just fine with taking my time on putting it together. The 440 looks brand new inside. It has flat-top pistons already. The problem is that they are way down in the hole. I have never seen pistons so far down in the hole as a matter of fact. The heads already have double valve springs. I guess I was thinking about building a 440 car just because I have never had a BB car before. The thing is I realize that there is a ton of potential in that 360 if I build it right. My fear is if I go ahead with the 440 build I may regret it and wish I had went with the 360. I'm not rich so $ is definitely an issue. Especially with the Mustang I am already building for my girlfriend...... I appreciate all the responses. Pretty much seems like most feel that a small block build makes more sense.....