Tank lift as promised.
This is a guide only, I take no responsibility in anyone one stuffing up etc atempt this at your own risk its pretty easy have a good look and see whats involved first before starting, measure twice cut once etc
Basically you can only do this with minimum of 50mm bodylift installed and this really only applies to 84-88 surfs/4runners as the hilux tanks are all ready in the higher position, why are the surf tanks 50mm lower you ask? because of the floor layout in the surfs having a rear seat the tank can't tuck up as far its very easy to do so long as you can operate a grinder a drill or welder the welder isn't necessary.
here goes,
I appologise for the fact I had done this before I thought of doing this and takin photos
Step 1
take your tank out
open fuel flap 3? screws around filler , get underneath truck theres two 12mm bolts up towards filler on the pipe down to tank undo these (unless you have lengthened the filler pipe when bodylift was done you will probably have these undone by now) undo the two or three small pipes to engine off tank or hardlines under truck,undo the three front and three rear tank gaurd bolts, undo the the three front bolts for tank,and three rear bolts for tank one of these doesn't have a captive nut on it so youl need a spanner as well I usually jam my knees under the tank to take weight off it once its all unbolted it should drop out throw it out of the way.
Step 2
Find this crossmember at the back of gearbox note right up on top the three holes that have no nuts, just below that halfway down the crossmember is a welded on bracket with three captive nuts on it (this was the front mount for the tank) notice how they line up perfect with the holes above the task now is to cut that bracket off in which ever manner you choose as to preserve the bulk of it and its nuts,
once cut off stick this up on top lined up with the three holes put your three bolts in tighten them up, at this point weld the cut off part in a couple of places to keep it there, this isnt 100% necessary as you can just have it loose and hold it there while you bolt the tank in, slap some paint on if you wish.

The desired end result
I have left a bit of the bracket so I can suport the front of tank on while doing up rear bolts

Step 3
Find the rear mount it hangs off the round crossmember above rear diff,
From the flat mounting surface measure up 50mm at both ends, draw a line then cut off give both bits a clean up,the cut off bit will now slide up the verticle face and the bottom tank mounting face will line up with the cut line, I had to cut out a small section in one of the ridges to get both bits to sit flush with each other and also drilled some holes across the face for some spot welds, you can now either weld or drill and bolt this in place
desired end result


step 4
You need to either buy a ute tank gaurd (as they are factory setup to suit what you have done so far) or adjust your one to suit the rear of it is left untouched as it just moves up with the tank but the front is two parts these are spot welded together all you have to do here is drill out these spotwelds, separate the to bits, then slide the two faces so the height is 50mm shorter
some triming may need done of any over hang respot weld, paint and you are done.
I haven't done this stage yet on this latest surf but have on my old one, so have no photos of the desired result but hers some photos of my gaurd as it is so you get the idea of what to do.


From here just reverse the removal steps the tank seam may need tweaked abit where it now meets the handbrake cable, then sit back and checkout the extra height you have.
If you have a hilux with a bodylift and deck lift or flat deck you could probably move yours higher than this point so bottom is flush or higher than bottom of chassis rails.
Thanks Stu