Super 6....can't put it off any longer. manifold questions

[gdizzle]

Ok my Slant brothers, please help walk me through the Super Six conversion. of course I am running the dart 66 with 225 with the original holley and rod type pedal. I have the article and read it 20 times. I have the materials list and I am ready. I also have the owners manual, and manuals for the Carter BBS.
I have found almost all the required parts. (just missing the throttle return spring, easy enough to fake I suppose with some angle iron)
My first concern, removing the manifold.
THe manifolds were removed when I had the engine rebuilt last year. He busted 1 stud so that one is now bolted on.
The rest of the studs dont have much thread showing, meaning I wont have much room for a thick gasket. I have 2 gaskets ready to go depending on what works best. I have the crushable thick Remflex. I also have the thin Felpro.
First question: if I am able to remove all nuts without busting a stud, why would I then remove the studs and upgrade them? Wouldn't I run a great risk of busting a stud in that process? The only reason I can see for removing the studs is so I could get longer ones so i can use the Remflex gasket. Please give any advice for the removal process. I have never done this before. Thanks in advance. You can see in pic the stud way at the front has no thread sticking out of the nut. And the manifold I am installing seems to have longer ends than the middle section. like maybe longer by 1/32 of an inch. if that makes any sense

 

[Slantsix64]

as long as you wd-40 them they should not brake i usually put two fell pro gaskets get a grinder and smooth both the exhaust and intake ports clean the the head make sure you have a clean surface and put some high temp copper silicone. torque it from inside to out should be fine. also i would do this when the car is cold not after a drive just in case due to heat. Super six is the best. after you have it on you ll never go back

 

[mvh]

Your old studs have been through 10,000 heat cycles and are brittle. New studs would be tougher, but yes, there is the risk of breaking them trying to remove them. I was successful leaving the studs and using the Felpro gasket plus Hylomar aerospace gasket sealant. Since you are using new manifolds (new to the car) you should loosely bolt together the intake and exhaust manifolds (very loosely, just so they don't fall apart) and stand them up on the head mating surface on a known flat benchtop, and check that the flange thicknesses match at every position. I had to file several flanges where one was thicker than the other, so that the triangle washer would only have been pressing on the thicker one (or it would have cocked, locking that flange in place -- see below) -- this would have caused a manifold leak. You really want to perfect this as much as possible to avoid vacuum leaks, exhaust leaks, or both.

Here's the thing abut these super long six-cylinder manifolds -- you cannot use a thicker gasket to compensate for an irregular surface, like you might be able to do in some other scenarios. Because of thermal expansion, they actually need to be free to slide in the front-to-rear direction -- that's why the torque spec is so tiny. Anything that keeps them from sliding will probably cause a cracked manifold, and any irregularities in the mating surfaces or uneven torque will cause a leak.

 

[slantsixdan]

Refer to this article and this thread.

Yes, there is some risk that you might break off a stud if you go to remove and replace them all, but figure it this way: those studs go through thousands of thermal cycles. That causes metal fatigue. If a stud is about to break, you have a choice: do you want it to break as you're tightening the nut while installing the manifolds (thus necessitating complete re-disassembly and doing the entire backbreaking job all over again)? Or would you rather have it break with the manifolds off the engine so you can get right to work removing the broken-off stub and not lose time undoing the manifold install only to have to do it again? There's only one right answer to this question.

Besides, removing all the studs gives you a chance to fix that hamfisted "repair" (a bolt is not appropriate as a replacement for a stud here; that's begging for problems down the road—this does not bode well for whatever other work was done by whoever decided to take the slackaѕѕed lazy way out instead of correctly replacing the broken stud) and you can also take the opportunity to make sure each new stud has appropriate thread sealant on its cylinder head end so as not to have to deal with coolant leaks later on.

The rest of the studs dont have much thread showing

When you buy new ones, make sure to get the correct length.

meaning I wont have much room for a thick gasket.

Fix it (correct-length studs) so that you will, or you are setting yourself up for frustration and aggravation. The Remflex gaskets are enough much better to be worth doing whatever is necessary to get your setup back in correct shape to accept them. That goes for both the manifold-to-head gasket and the intake-to-exhaust gasket (the stamped sheetmetal type in the Fel-Pro kit almost never seals fully).

Please give any advice for the removal process

Thread two of the stud nuts onto one stud. Jam the nuts together with two wrenches. Then put a wrench on the nut that is closest to the head and pull—don't jerk, but pull smoothly—with your wrench.