What kinda leak is this?

One thing you can be sure of is that a mechanic on the clock isn't going to leave his bay tied up waiting to torque down the intake.

Maybe they would push the job off to the side while the RTV cures, but that is also one of the points of The Right Stuff.  It cures through and through quickly.

Dave, I have an aluminium intake and the instructions (rightfully) say to never use a turkey pan.  

I understand that it keeps oil from coking on the bottom of the exhaust crossover, but I don't find chunks in my oil.

On the AMC's you MUST USE the "turkey pan"  (even it it said not to) and move the little pan / cover from the stock manifold to the after market one or you have and oil use issue.

The PVC is at the rear of  the intake with rubber grommet and if the 2 pans are not used the PVC sucks up oil vapor. You don't see any smoke out the tail pipe but you go through a lot of oil not knowing where its going!

You sometimes get this when the PVC is in the valve cover (after market mostly) and there is not a baffle used under where the PVC is installed. No smoke but the oil is going somewhere?
Dave ----

Thanks guys!

Sorry for all the stupid questions, but I’m relatively new to working on cars other than basic stuff!

Few more questions:

- So if it is the intake manifold, it’s okay to use RTV *ONLY* on the front and back of the walls? So I’m guessing on all other parts of the manifold I would use gaskets?

- Do you guys have a schematic on torque specs, or do you guys just bolt it down with some good torque?

- What is the difference between RTV, Ultra Grey, Ultra Black?

- When you finally mate two surfaces together with a sealant, the sealant obviously squishes out the front, but doesn’t it squish into whatever part you put it on? Wouldn’t that mess up parts on the inside of whatever system you’re using it on?

Yes, you still use intake gaskets, just not the 'Great wall of China' wavy front and back seals.

Too many people use WAY too much sealant, and it does squeeze out.
The only time I use a bead is on a diff cover or something like that.

You wipe on a film, with your fingertip around the water ports front and rear.
(Almost thin enough to see through)
And if you use the wavy seals you put a tiny dab in the corners.

RTV means Room Temperature Vulcanizing. All these silicone sealants are RTV.
There are a few different cure types.
Perhaps you remember the old acetoxy cure that smelled like vinegar? (Acetic Acid cure)
Ultra Black is supposed to be more oil resistant, while Ultra Gray has better elasticity.
I use grey because my engine is grey and it blends in.

What he said /\  /\  /\.

As for torque values and sequence, I always use the factory shop manual's values, usually shown on the last page.  For you the page is at Documentation/Engines/Windsor and then the Windsor Instructions tab.

ArdWrknTrk wrote

You wipe on a film, with your fingertip around the water ports front and rear.
(Almost thin enough to see through)
And if you use the wavy seals you put a tiny dab in the corners.

Seriously... what would I do without you guys!? Learning so much. Love this forum!

Nope.

When you have the intake off place a headless bolt or short piece of threaded rod in one vertical bolt hole at each end of both heads.
(it may help if you can cut a slot in these 'screws' with a hack saw or .045 cutoff disc in a grinder)

Now the intake gaskets can't squirm out of position as you lower the intake and start tightening it.

Okay, if you have everything clean, laid out and ready, using your finger smear a little bit around each of the four water passages.
Now you can drop the intake gaskets in place and apply another film around the passages, right on top of the gaskets.

Go ahead and apply a really high bead of RTV where the front and rear gaskets would go. (Straight from the tube, none of that reducing nozzle)
You want it to squeeze out, so make it taller than the gaskets you're not using.

The 'screws' in each corner will help guide the intake. Just be sure you set it straight down, evenly.
Loosely thread in all the other bolts before removing the 'screws' and replacing them with the proper bolts.

I torque in stages. For these trucks it seems okay to just snug everything down evenly, then follow the inside out pattern going maybe 75-80% of the torque value.
At this point Gary lets it set up.
Which is not a bad idea.
Try to get a look at the back side and make sure the RTV is meeting the intake all the way across the valley.

When you go back to bring all the bolts up to full torque you must follow that pattern again.
And me, I go around one more time at whatever my final torque spec is just to make sure.

Hell yeah! Thanks brotha!

It's just what I would do....
There are many better mechanics out there.
For me it is a combination of expedient and best practices.
Someone will say "you don't need -or shouldnt- do that".
I'm sure someone else will insist that I must do 'X'.

And that's great. I have an opportunity to learn something new.
Or at least try something new, even if it doesn't work out for me.

I hope you can track down your leak, and it isn't too hard to fix.
I've had an oil pan leak forever.
But I haven't found the stars align for me to pull the engine out to replace a $20 gasket.
I AM prepared though!    

Update!

Here is a new pic after the undercarriage was cleaned. Any thoughts?

It can still be the rear main or the back of the intake manifold.  If either leak the oil will show up there.

I would be looking on the topside, for a leak at the rear of the intake.

If there is no oil there then it is almost certainly the RMS or coming through the crank flange bolts.

(I forget if your engine has gallery plugs behind the flywheel)

Curious as to how many miles your truck has on it?  Mine, also a 351W, leaks there too and it is a rear main seal. Drives me crazy, but I'm not pulling an engine to fix it.