Grayish Exhaust, Oil at Engine/Exhaust connection?

[JasonTL]

So, among the other myriad of things I'm working on is this. The car puts out whiteish/grayish, perhaps bluish(I wouldn't call it blue but maybe some do) exhaust when I start it up and sometimes when I accelerate.
Also, when looking down at where the exhaust pipe connects to the engine I see what looks like oil and occasionally the same kind of smoke coming from that connection.

I have previously had a new exhaust system put in from the tail pipes to this connection.
I also had the head gasket replaced. The one that was put on had sat in my house for about a year before I got it put on, could it have gone bad?
Some other research I've done suggests perhaps piston rings?

I don't know exactly how much oil it's burning because I currently have another oil leak. I do know it's putting out a little more exhaust than it should and there shouldn't be any oil-like substance on the exhaust pipes.

Thoughts? Would some pictures or video help?

1988 GMC Suburban, 5.7L 350CI

 

[Quest]

If it's blue-ish smoke-->oil burning past piston rings.

If it's grey-ish to black-ish smoke--> engine possibly running a tad rich, or cat is not working...

Q

 

[Clevy]

If you see the smoke primarily at start up and when you accelerate I'm leaning towards worn rings.
Last week one of my employees brought me his suburban to change oil,transmission flush and plugs.
His plugs on the drivers side were all wet looking with oil and it was obvious the rings were worn on that bank of cylinders.
I put Pennzoil Conventional 10w30 in the sump and 1.5 cans of mos2 in with the oil,just to try improve his mileage a bit.
As of this morning there is no more smoke at start up and he says the engine usually drank a quart of oil every week but this week there is no noticeable consumption based on the dipstick.
I know mos2 is a superb friction modifier however I was very surprised to see it also helps worn rings.
I know it builds up a friction reducing layer on all moving contact parts so I assume it built up a layer on the cylinder walls,creating a better ring seal.
Give MOS2 a shot. It's cheap and worst case scenario is that you get better mileage.