After purchasing my new tank a couple of years ago, I looked at my new tank for the first time yesterday (it was still in the box) and I also have the bolt in the bottom that you all are talking about. Then I realized that olblu49 is correct! Now that I think about it my TF tank outlet is at the top and is integral with the sending unit and the outlet on the bottom (in the case of TF trucks) is only there for a drain. I removed my original tank yesterday and it didn't have any drain in the bottom at all. I left the bolt in and installed the new tank with no problems except it didn't line up properly with inlet and vent hoses. After some struggle I managed to make it work OK and everything seems like it might work. I'll know when I put some gas in later today.
