Depending on your Budget, you can always have Fuelcellguy make one for you. He does excellent work and he'll make it fit anytpe fuel feed you need.
EDIT:
Just found this for an 82-86 Blazer Fuel Tank
FUEL TANK
25 Gal., (28-3/4 x 28-1/8 x 10-3/4), w/ Lock Ring Sets, Depth of Bottom Half 3-1/2", Small Filler Pipe 1-5/8" ID, (Hol#197-1273) (SPI#GM15B)
http://www.truckpartsdiscount.com/cg...ar=1986&cat=67
Looks like fuel size late model might be a hair to big