1999 G16 Smoking and using oil

[slowride77]

First post, sorry if i am missing something.

I have a 99 G16 that i recently bought and have been working on to get it running better. It ran when i bought it, but both clutches were trash among some other some things, and i found out this isnt the original engine. Numbers dont match.

My last problem to tackle that is really driving me nuts is that it smokes at start up and every time you really get into the gas. Just a single white puff, kind of large, then it clears up after you get going. After reading a lot of posts on this forum, i have checked the compression, oil in the airbox, the breather tube from the valve cover and spark plug.

Compression was 175 psi, there was/is a slight oily film in the smaller airbox chamber, but no standing oil, just a residue, it is oil though. The breather tube is clear and free. The spark plug was old and i changed it to the correct ngk, had a ac delco in it. After changing the plug, i drove it around like 20 minutes and check the plug again. it was completely black and charred. Not oily, but black and covered in dark deposit. The oil was down about half the dipstick (6 oz) after the long drive.

SO, i haven't changed the oil yet because the guy before me had changed it. Now i read on here that the dipstick could be wrong (its not lifted). But to note, i did fill the oil to the top of the range on the dipstick and it did smoke more the next time i drove it. I also read about BBQ the muffler, which i havent done.

I just dont know where to start to attack and i dont want to do something that isnt needed, for time sake. PLease help! THanks!