Here's a thought . . .

In the "boat" realm of things, they generally use a portable fuel tank.
The tanks are available in 3 gallon or 6 gallon sizes (WalMart has the 6
gallon size and Academy carries the 3 gallon size--both about $25.00
range or less).  

In the area at WalMart where the tanks are, there are lots of
accessories for the fuel tank.  One is a "primer bulb" that is put
between the fuel tank and the boat engine (as in outboard engine).
There are sizes for 5/16" and 3/8" fuel lines.  So, about 5 or 6 feet of
rubber fuel line, the primer bulb, a few hose clamps, plus some gas, and
then you can attach the boat fuel tank set-up to the fuel pump of the
engine (blocking off the car's fuel supply line at the same time).  This
will allow you to start and run the engine on "fresh" fuel rather than
what's in the vehicle's fuel tank.

On the earlier carbs, the "bowl vents" can be used to put fuel in the
float bowl too. but that takes some finesse to not also pour it down the
carb throats at the same time.

ALSO, in the various accessories for boat-specific things, there's a
pump kit to do oil changes with.  It's about $20.00 and amounts to a
suction pump with dedicated hoses attached to it . . . smaller line goes
down the dipstick tube and the other line goes into a jug to catch the
old oil.  You can also buy similar suction pumps from Harbor Freight for
about $10.00 or less, but you'll have to assemble the lines it comes
with to do the same thing.  Or even in the automotive area at WalMart.
It can take a little while to do the pump action, but you will only have
to get under the car to change the oil filter that way.

Enjoy!

C-BODY