The question involves safety and I'm definitely no expert here.
A tank behind the rear axle does a "Pinto" in a rear end collision.
Side mount tanks outside the frame rails have a similar fiery end in a T-bone collision.
Inside the frame rails and before the rear axle is safer.
If you plan to install a performance engine and rear axle to go with that 4 link, the drive shaft will now be under stress.
So a cage design attached to the frame rails is needed to catch the driveshaft and hopefully keep it from rupturing the fuel tank.
If you buy a kit, I would ask the seller what they recommend.
