Ever since i bought my 1981 suburban, before i ever did anything to it besides put the engine in, I have had a power draw whenever the rig is parked. The engine came out of another car i had, and when it was in that car i never had any power drain when the car was parked. With a fully charged 850 cca battery, the truck will drain the battery within 48 hours. I mean drain DEAD. From what i can tell, the only things drawing power (at the time of testing) are the radio, dome lights and alternator (im not sure why the alternator draws power but iv even replaced it and had the same reading with the new alternator). Every body has a radio, and the only power its drawing is just to keep the clock memory. Everybody has dome lights and when the door isnt open, there should be no power draw. Alternator? I have four cars including this one, and none of them have a problem with sitting for long periods of time, and they all have alternators, radios, and dome lights. I have a nieghbor with a 1977 chev pickup and it has the same problem, dead battery over night. Is there a common problem with power draw on older chevs? maybe perhaps a switch that goes bad? In order to not have to start my truck every day and waste gas iv had to install a battery maintainer. This device is prolly a handy thing when you have vehicles that only start a few times a year, but without it i have to jump start my rig every week. Kinda pathetic.