I don't think you have to have one. It just helps prevent alot of minor problems. Fuel purculating in the carb at shut down issues are one. The hard to start on hot days after driving only a short time previously, different kind of bogging down issues when you have too much fuel in the carb. Even a well tuned carb has some impact from sharp acceleration, deceleration and acceleration again (not that you would be doing any of that). I'm sure someone else can come up with alot more explanations why it helps. They are minor things and it all depends on how your going to drive your car. I'd think with a hemi in the car you will probably be pushing it on occassion just for the heck of it and you'll find out what I'm talking about. I had the same choice to make and I upgraded to the largest line from the fuel tank I could find. Then the smallest standard line back. I wanted to see if I could use the stock clips to hold them in but size made me have to use non standard clips. In the end for me I just wanted to be sure my engine didn't have any problems with fuel starvation. A problem with many high horse power engines using the standard lines that came with their cars originally.
