I isntalled a "Tanks, Inc." '49-'52 Chevy passenger car gas tank behind the rear axle.
Here is a thread I created that gives the basics: Rear Mount Gas Tank 63-72 Short Bed Step Side - ChevyTalk --The Social Network for Chevy Fans
I am runing a carb so I am using the regular mechanical fuel pump. However, Tanks Inc. also has an in-tank fuel injection pump that will work with their tanks. In-Tank Fuel Pump Module - GPA-Series