Gas Tank HELP!
 

I have a 1984 2wd Blazer. I bought the blazer almost finished, except for some major details... The gas lid has been shaved. The stock gas tank wont fit because of the inset roll pan... So it has a fuel cell sitting it back. I was thinking about hinging my tail light for the filler cap.. So.... I need a fuel tank that would fit in a 23 by 27 hole. Didn't know if anybody else has accomplished this sort of task. Thanks for your help!