For those who are "skeptical" about the merits of this petition...
May 29, 2013 — What Chrysler knew, and when they knew it, will overcome reasonable doubts. At the following link you will find what is called the "Baker memo."
Please note the red box on Page 2 of this 1978 memo:
"Chrysler is investigating fuel tank relocation ahead of the rear wheels for vans and multipurpose vehicles, but present plans for pickups through 1983 and for MPVs and vans through 1985 have the fuel tank located behind the rear wheels. In vehicles both with and without bumpers there is a concern with vertical height differences that create a mismatch with passenger car bumpers. Where fuel tank location behind the rear axle is all that is feasible, a protective impact deflection structure may have to be provided whether or not a bumper is provided. An investigation whether to relocate the fuel tank or to provide impact deflecting structures is presently underway."
This memo has been on file with NHTSA since June 2010.