Under car gas tank: How bad an idea is this?

[Evil_Fiz]

Since I am doing a Subaru conversion on my 70 Ghia convertible, I need to find a location for the radiator. The opening for the gas tank looks really tempting in order to keep the cutting and fabricating to a minimum. But relocating the gas tank to the rear luggage compartment using a safety cell will add more weight to the rear of the car and lead to more fabrication by way of a new firewall.

So my (most likely misguided) thinking is to have a 152cm x 134cm x 5cm aluminum gas tank built and mounted under the cabin. This location "should" keep it away from most vehicle-to-vehicle impacts. The car will only be street-driven and will have 4" ground clearance at the lowest point on the rockers.

How bad an idea is this?
(I am posting here BC no other forum seems appropriate)

-----
Emil

[Ol'fogasaurus]

Check the law where you are at. With some of the lane marking "turtles" being bigger than other "turtle" markers (the little domes in some of the lanes) on the street 4" may not be enough to safely go over them. I bent up the pan in my lowered Pinto once by hitting a lane divider turtle (taller and a larger dia.) which are bigger than the other lane marking turtles.

Some places the minimum height is the tire on the rim but with no air in it and nothing touches the ground with you in it.

Lee