I have a 350 small block, carburated..no smog crap or A/C. Its a fresh rebuild. And I used 3.5 quarts in 300 miles. No smoke anywhere from exhaust and no visual leaks in or around engine..any ideas??? PLEASE HELP..

 

are you sure you put a full 5 quarts PLUS enough for the oil filter?

if you BURNT 3.5 quarts, your exhaust would be a cloud of blue smoke everytime you start it up, and if you were leaking it, you'd have puddles and puddles, 3.5 quarts slicks out huge on pavement...

was it a complete rebuild? rings and valve seats are the main cause of internal oil loss...hopefully these were both done

 

Yeah, the oil filter will consume a good quart of oil believe it or not, when you put a new one on, you have to make sure you fill it. Do you ever smell oil while you drive, or when you come to a stop? Keep checking for leaks when you turn off the car, or check when it warms up and is idling. Fill up to about 5 quarts again, and then see if it goes back down again.

 

when i did a complete rebuild of mine, i think it took close to 7 quarts of oil for the first start up. You gotta realize, there is absolutely no oil in there to start out with, and normally when you do an oil change, it takes a full 5-6 quarts, and you never get all the oil out when you change your oil..

start your car up, leave it sit for a while at idle, go eat a sandwich or something and come back in like 5-10 minutes and see if there is a puddle...then turn it off and let it sit for a couple hours and see if there is a puddle... I don't believe you pissed out 3.5 quarts or burnt it...becuase you would definately know..

like posted about, make sure you are full of oil according to the dipstick before you do this..

 

Ive been driving it for 3 months now with no problem. Then I went on a trip and drove it on the highway around 80mph for like 300 or so miles and then I stopped to get gas and I checked my oil and thats when I noticed it was really LOW I did a complete rebuild and I used all new rings and the heads were totally rebuilt also. Im at a total loss. Its not smoking or leaking and I dont smell any oil burning while stopped or moving.

 

When you do a new engine rebuild, it will usually consume some oil anyway because of the rings seating and things of that nature. Do exactly what these guys said. Start the car AFTER FILLING TO THE CORRECT AMOUNT, and let it idle. Come back in 10 minutes and check for a puddle after you shut the car down, then check the dipstick.

 

There is your poblem,your either not vented properly or your sucking oil up through your pcv valve. I've seen that much oil burned on a trip of that nature and not notice any smoke.