Fuel Cell- Where to mount it
Fuel cell in the spare tire area for many reasons. The 2 biggest are:
1. Accessibility....You will be adding fuel often, but your spare tire will get almost no use at all (hopefully). For that reason I would put the thing that gets almost no use (spare tire) in the most inconvenient to reach area, because you probably won't need to use it.
2. Weight transfer....You wan't the weight as far back, and low as possible to help the car hook (assuming you race on occasion, and like traction). If it were me, I would sink it in the spare tire well. Just remember, per NHRA rules, if you have the sump hanging out side of the body you will need to shield it with metal.