I had dumped about 10gallons of diesel into it when we first got it running and that brought it up to about 1/2 tank on the gauge.
It has not moved during all my testing so today I thought I had better fill it up.
Went to the gas station and started to fill.
Only got 1 liter in before it gurgled out the spout.
I used the stock filler and vent tube which turns out to be way to small for diesel as diesel foams so much easier.
Tomorrow I will hopefully get a full size truck filler neck and tube in as well as a second vent line.
I don't think power is a problem, lots of pickup and GO!