Your crankcase is getting pressurize. Usually blowby. Did you make sure you align the rings? Did you check the cylinders weren't out of round?
I'm not sure if this will help you. I still have my old 88GMC
> with the 4.3..When I got it it was useing a quart of oil a day!!..It had
> 74,000 miles on it when I got it. We put new rings in it and thats it
> cleaned up everything. Truck still runs good but the last couple years it
> would blow oil out the dipstick. The truck now has 228,000 mile on it. I
> never did find out why but always thought it could be the CC seeing it was
> burning so much oil when I got it. The way I fixed it was tape the dipstick.
> Electrical tape works great!!! But I only got alittle oil out and it would
> run down the dipstick and onto the manifold and smoke!!!
>
>