I moved my tank to the rear primarily to get rid of the gas smell. Even with new seals and gaskets it almost always smelled in the cab, especially in warm weather with a full tank, since the vented cap was right next to the drivers window.
http://67-72chevytrucks.com/vboard/showthread.php?t=390279
Tin tanks under a vehicle have a relatively short lifespan.
I agree that it's great to kick differing opinions and thoughts back and forth. As far as the lifespan of the tank goes that really depends on the climate the vehicle is used in. Here in Colorado where I live my experiences have shown that the arid climate and lack of the use of "salt" on the roads makes the gas tank last as long as the vehicle.
In 1967 the National Highway Traffic Safety Administration (NHTSA) introduced the Federal Motor Vehicle Safety Standard (FMVSS) No. 301, “Fuel System Integrity” [NHTSA Part 571.301] to reduce deaths and injuries occurring from fires. Initially the standard only applied to passenger cars, however, in 1977 light trucks were also included. GM no doubt saw thsi standard lurking on the horizon and redesigned the fuel tanks outside the passenger compartment. As far as GM's Safety vs. profit record they actually did a study on this subject in 1973:
At the heart of GM's resistance to improving the safety of its fuel systems was a cost benefit analysis done by Edward Ivey which concluded that it was not cost effective for GM to spend more than $2.20 per vehicle to prevent a fire death.While this was certainly done in response to the side mounted tanks that were used on the "new" 1973 models, it shows that safety wasn't job one at GM, profit was.
