Taht's a cool looking tank. 
Are you not supposed to put screws into the floor?
Yes you can screw to the floor but the fuel drain hangs below the brackets feet.
Maybe you could fab some brackets and bolt it to the engine?
It's a little big to be bolting to the motor .
omar those are bad ass, how far below the bracket does the fitting hang?? i'm thinking that you could get some aluminum blocks to make up the difference and just bolt it to your floor. 
The extension hangs down about 2" below the mounting bracket feet . I was actually thinking of cutting two 2" holes about 6" apart and then cutting the section out between them to make a long hole with rounded ends just for the fittings and hose to sit in . I figure I already have a hole in the bilge area for the sub floor area to drain so it wouldn't be a big deal .
I also thought of screwing and glassing some 2x4 to the floor with some through bolts in them to mount to . At the races it'll only have about 5 gallons in them anyways so it wont be a huge amount of wieght sitting there .
I guess I'm gonna have to pull out my official Mickey Mouse ears and Official Mickey Mouse certificate and see what else I can do . Keep the ideas comeing though.
-beerjet-