I place the fuel tank many centimeters above or below the carb on MANY dozens of planes.

Except for on the ground siphoning it makes almost no difference. Our planes would be unflyable otherwise.

Hint: on an 1.20 size plane or larger during an upline the fuel centerline is a good 6-8" BELOW the carb and the engine still runs fine.

Larger planes with the fuel tank on the wing tube see even larger centerline to carb differences during normal flight.

This is an example of what was originally good advice ( to prevent siphoning ) taken out of context with unfounded effects read in.