first of all, $5/gallon gas is a rumor. Might happen, might not. I bet if it does, there will be rioting in the streets, and politicians and oil company ceos will be getting tossed out the window.
Second, find something else to be your daily driver. That way, this car can be something that you take out now and then to have some fun with. An evening on the town, dinner and movie, for example, can easily run $100. This is just another form of entertainment, so instead of dinner and a movie, you just fill up your tank and go to a cruise.
Third, unless you are going to race the car, dont go balls out on the mods. Built engines are a pita if you are just going to drive it on the street. A stock 383 or 440 in an a-body is going to give you great performance, great reliability, and decent gas mileage. There's not going to be that much difference in gas mileage between a stock 360, 383, and 440 anyways. You can still put in a mild cam to get the lope, loud pipes, and use a small 4-barrel. If the $5/gallon gas never happens, then you can just swap carbs.
Fourth, how many chances are you going to get to do what you want? Put the 440 in and deal with what happens, instead of worrying about what might happen.
