tell me if this is safe

[matthufham]

when i bought the truck the p/o had put a keg in the bed used for a gas tank. it had 3/8 hose to the fuel pump and worked fine. i now have a blazer tank but i still want to keep the keg. the blazer thanks has 5 fittings on it, here's what i have.
1)filler 1 1/4"
2)vent 5/8"
3)open 3/8"
4)charcoal canister (capped)
5)sending unit to pump

i was thinking i could use that 3/8 fitting by running hose to the keg and then i can use it as an auxilary tank. what i want to be able to do is fill the blazer tank and fill the keg with gas. the keg will gravity drain into the tank until all it's gas is gone, then the blazer tank's gas will be used. i can then go twice as far without filling up.

Is this safe? the keg is way stronger and better fit to hold gas than the blazer tank and i don't think it'll leak at all, so it seems safe but my dad says it's dangerous. i'm pretty sure he just doesn't want the keg to go back in the truck when all is said and done though.

so i ask the experts. or

i found a pic