I am installing the exhaust manifolds on my 57 312 Tbird, the manual calls out a Graphite grease to be put on the mating surfaces. Can anyone recommend a brand of grease? Should it be a dry grease or a wet grease? I have both but am not sure.

I didn't use anything on mine no problem.

i use the gaskets with grade 8 capscrews and hardened flat washers. recomend the thicker flats from cat dealer. .use the greas to lube the threads on grade 8 cap screws

Please, use Never seize, or equivalent product.    graphite is very old tech now. 
I use it on ever nut, bolt, gasket, matting surface..

CSPIDY.  IF you were to dig through the Forum Archive, there has been a lot of back-and-forth at different points in time regarding the use of exhaust manifold gaskets on Ford y-block 239 - 312 series engines.

My understanding is that most, if not all, gasket makers have historically included exhaust manifold gaskets in their y-block rebuild sets.  However, it has been pointed out that Ford did not use exhaust manifold gaskets on the y-block Fords when they were manufactured!

Discussion on the Forum has centered on ears breaking on y-block exhaust manifolds.  Discussion has pointed at poor heat transfer OR uneven heat transfer between the cast iron cylinder heads and the cast iron exhaust manifolds.  Cracking may be caused by
- the use of paper-like exhaust manifold gaskets resulting in uneven heating and expansion of the exhaust manifolds. 
- improper torquing of exhaust manifold bolts OR exhaust manifold bolt torques CHANGING over time due to the heating and cooling cycle of the exhaust manifolds. 

The use of a graphite based grease or something similar like Never-Seize has been recommended as a material that will serve to eliminate minor surface variations between the iron surfaces and eliminate potential exhaust leaks.  Warped exhaust manifold mounting surfaces can be re-machined to eliminate exhaust leaks if necessary.  

As Cliff reports, his years of Caterpillar experience have shown him success with the use of exhaust manifold gaskets coupled with Grade 8 fasteners (bolts AND flat washers).  I don't know that Ford used anything special in their exhaust manifold hardware other than brass exhaust head pipe nuts.  Grade 8 bolts AND flat washers may cure the reported changing of torque reading of exhaust manifold bolts AND the uneven heat transfer issue.      Like Sanddoc, in my experience I have had success with Never-Seez on all of my exhaust manifold bolts, header mounting studs, and metal to metal exhaust header to cylinder head mating surfaces. 


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Have you milled flat the head & manifold mating surfaces? If not, you might be better off with gaskets. If you are careful to not unevenly over-tighten the bolts (and crack a manifold ear), the inevitable exhaust leak 'ticking sound' (often mistaken for valve noise) will never surface. Since the manifold bolts thus shouldn't be torqued to spec., I recommend the locking type. Just remember to loosen the Allen screws before attempting removal.

6 VOLTS/POS. GRD. NW INDIANA

Good stuf 2721955metor/No Shortcuts, This is my first go round with a Ford Y-Block.
I did try the search function but didn't see anything on cracking exhaust manifolds. Is there another method to search old threads?
I use anti-sease on all the bolts, (C5a) I am planning on not using any gaskets this time, just looking for the best coating for the mating surfaces.
As you have mentioned the first replacement manifold cracked at the aft flange bolt ear, and I had gaskets between the manifold and the head. Yuk! It was a remanufactured manifold, not sure what that means. Didn't see any evidence of weld repairs.
I understand the the thick flat washers but not sure what the grade 8 bolts bring to the party. I get the feeling that you do not want a high torque on the bolts. Maybe stay on the low side of the recomended torque?
Unfortunately the engine is in the car so surfacing the head is not an option. I did check the surface with a straight edge and looks flat.

Daniel Tinder
I believe you are speaking of locks for the manifold bolts, I looked high and low for a locking method for the bolts but only came up with stainless wedge-lock washers, which act like a ratchet. Made by "Clips". I would prefere at solid locking method. Do you know of a supplier for the Y-Block engines?
You say not to torque to spec, then what do you torque to?

grade 8 bolts are more elastic than 5,so they will strech as manifolds expand and return to wher they wher torqued to when cooled. the way ford made the manifolds with over sized bolt holes created lots of issues.my first decent car with a 272 y was constent issues with bolts coming loose.when i converted to dual exhaust,1 new manifold 1 side,used geade 8 and hardened flats no more isues on that side. eventually replaced bolts and ist gasket on pas side  and that cured the problems with ex manifolds for me

Great answer, makes a ton of sense