I once bult a VW sandrail and I used a freon tank for the gas tank. It was nice because (with VW small engines) I was able to remove the fuel pump and used just gravity feed from the tank. Now, I may get flamed here for what I did but.. someone else welded it (same guy that welded the frame kit) so safety was not my issue (he had done others). I am not recommending it but this thread just brought back the memory to share.