I crawled under the back of my '73 C-10 with the hope of putting a Blazer tank in it. I measured ~27.5" (if i recall correctly, it was a few days ago) between the frame rails. How does the Blazer tank fit in there? Or was there a running change in later years and the frame was slightly widened? I'd really like to put a Blazer tank in it if at all possible.