im building an 80 pickup w/ a sbc 350 and full width axles. i need my front springs to carry the wieght of the 350 but still flex like a motha. using skys full width kit and thinking it will make the front even more stiff b/c the springs are farther apart then stock. TG makes HD 5" springs but i dont know if those will flex enough. the truck will only be driven off road so street drivability does not matter. should i use the HD springs up front or just more lift.