OK, it's a little hard to see on my setup:
http://i54.photobucket.com/albums/g110/eletrikal/Picture038.jpg

So i got this picture to possibly help:
http://i54.photobucket.com/albums/g110/eletrikal/quad2.jpg

Now, in observing the top 2 pictures we notice that the vaccumm port for the vacuum modulator thing on the transmission is closer to the right bank of the engine than the left bank.

Let's just say, for argument's sake, that the transmission modulator is bad (leaking).

Do you think that this could cause the fluid to be sucked only in the direction of the right side cylinder bank because the port is closer to the right side thus causing smoke to billow out of just the right side exhaust on a true dual exhaust system much like the smoke machines at various hard rock concerts that you might see in the 70's, i.e, KISS, aerosmith, rush, triumph etc.

Which was my original problem.

A little background:
The engine in question has had a recent head gasket replacent---on the right side. Felpro part # 7732---the blue one. When i ran it on the test stand no smoke or steam. Ran good generally.

When i got it back in the truck the thing after a minute or so started smoking again a little mostly out of the right side exhaust. So i was a bit crestfallen. But this was a vast improvment over the "fog machine" situation of 4 weeks ago; (This was when truck did an excellent immitation of James bond's silver aston marton of the 60's) So i decided that i would live with it if it didn't get any worse. So i drove it around yesterday stopping every now and then to see if the smoke would subside. Now somewhere along the line, the transmission modulator line fell off the canister----because the truck would not shift into second and also because i visually checked that it did indeed fall off. But also, the smoking stopped. So i drove it around some more and no smoke or steam whatsoever.

What is your opinion? Do you feel that the vacuum port being closer to the right side of the engine could cause trans fluid to only be sucked into the right side cylnder bank and thus cause smoke to come out of only the right side exhaust on a true dual exhaust system?

I went through the same thing on my brothers '69. After replacing a blown head gasket I got the smoke screen you describe. I determined the muffler was coated with oil inside because the smoke started after the mufller got hot. I replaced the muffler and there was no more smoke.

ever hear of gravity ?? is there trans fluid in the line ?? what color is the smoke ??

well vacuum is being pulled equally in both directions. while the intake valves are close on one side the intake valves are open on the other side, It happens quickenough to create a constant vacuum but enough lag to get oil to both sides. I would assume something else is wrong. Check the lines as 68kmeno says.

simple deal, stick a wood toothpick into the vacuum fitting on the modulator. if it comes out anything but as dry as it went in, the modulator is leaking. tranny fluid will drip out of the line if you pull it off at the bottom.

even a quick look at the manifold shows that the runnue in question feeds the #5 and #8. all the other runners feed one cylinder on each side too.

FWIW, I believe we are all GM Tech's, most of us don’t get paid for it. I liked the quote that someone has on all there post's. "A amateur built the ark and professionals built the Titanic." :)

Add'l info:

Alright, some smoke was coming out of the left pipe but it was much less than the right pipe and it was intermitent. When the tube fell off the vaccum modulator at the trans, the smoke immediately stopped. And the truck wouldn't shift into 2nd.


Do you feel it is possible that more fluid would be sucked into #8 cyl vs. #5 cyl causing more smoke to come out the right side pipe vs. the left side pipe.

first thing to do is check out IF its trans fluid thats burning ... does the vac line from the Modulator have tran fluid in it ?? if so replace the Modulator first .... as for your question YES it is posible that the bottem of runner in the manifold is tilted to one side allowing the fluid to flow more to that side ... but you also may have a intake manifold to valley leak allowing oil to be pulled into one or more intake ports .. thats why I recomend looking at the line on transmission for fluid first ....

Stewart,
If the vacuum modulator is leaking it will mostly go to the cylinder thats closest to that vacuum port.Some will get drawn into the adjacent cylinders
pulling the spark plugs on cylinders 6 and 8 will tell the tale.
If you pull the hose off at the modulator and see fluid drip out the hose or the vacuum mod nipple it means it has to be replaced.
If that is your problem thats an easier job then a head gasket.:D
My brother just recently went through the same thing on his Chevy p/u, it took a couple of days to burn off the fluid that had accumilated in the exhaust system but then it stopped smoking.

OK, it looks like was the vacuum modulator; Truck runs pretty good with no smoke or steam whatsover now.

So, after about a month and two, not one but two engine swaps it turns out the problem could have been very likely solved with an $11 part and about 5 minutes of work.

Yeah. i'm happy that the truck is running right, but i'm not happy at all about what happened over the past month.

But i did learn quite a bit.