Hello Everyone,

I appreciate all the knowledge and insight into this topic. On my 4th attempt, I think I have it sealed. (Knock on wood because it has only been 2 weeks of leak free service). I admit, I am a hobbyist, not a professional mechanic. And the method I use below would not be advisable if I had to do the job at flat rate. I'll describe what I did below and anyone can feel free to criticize as I know there are probably better ways. But any FE builders out there who might benefit from trying this method are certainly welcome to it, especially if you kept fighting leaks shortly after reassembly. Given I failed the first 3 times, maybe someone can benefit from my blunders. Keep in mind, each blunder means about a full day if not more of work plus the expense of gaskets.

Using cork end seals or not?
I tried to follow Edelbrock and Permatex's intructions to not use the cork twice and had a leak after 3-4 hours on both tries. I called Edelbrock twice and they finally said, it might be better to use the cork if I've tried RTV twice and it leaked. The compressed thickness of the front and rear gap on my manifold was 3/16". The instructions say to lay a bead of 1/4" RTV down. I did this and used the "Right Stuff" which many swear by. My experience is that 1/4" is just a lot of RTV to apply having 2 disadvantages. First, I was really nervous about it covering up an oil whole in the corner or have silicone break off and it end up fouling my oil pump. Maybe I am paranoid. Second, with that much silicone, you are bound to have a thin spot or a void. When I pulled the engine apart on both failed attempts with RTV only, both had a little pinhole in them. To each his own, but my experience taught me, RTV only doesn't work consistently. I know others have and will swear by this and I can't dispute them except to say, it didn't work for me.

The third attempt I did use the cork. I glued it down with brush tack. I was nervous about doing it this way because I wasn't sure how good of a sealant brush tack really is for oil. I put a finger full of RTV down on the corners and sat the manifold down. I gradually torqued it watching the cork to make sure it didn't squirt out. This is nerve wracking. I thought I had it done well. I then let it set up over night (26 hours) and installed my pushrods, rockers arms and set my valves (adjustable Harland Sharp). I finished the top end and fired it off and once to operating temperature, the passenger rear corner was leaking. You can imagine how PO'd I was. I immediately pulled it apart to find the cork hadn't squirted out, it squirted in leaving a gaping hole there. The RTV helped seal the corner, but about 1 inch in (just past my finger full) the gasket squirted in and left a nice slot for oil to leak.

So I developed a new plan.
The problem with using RTV only is there can be voids and that is just a lot to use.
The problem with using the cork only is that when torquing, the cork wants to squirt in or out.

One of the forum members suggested using contact cement. I contemplated that but was concerned it may not help seal imperfections in the cast surface.

So what I did was use a hybrid approach. I temporarily installed the manifold with RTV on the bottom side of cork. Removed and then reseated. Sound odd? Here is how I did it:
1) Clean all surfaces super good. I scraped, cleaned with a brillo pad, used brake cleaner etc.
2) I used Gasgacinch to place the intake port gaskets in place with a thin film of RTV around the water ports. I chose to put this gasket down so I could make sure the tabs line up perfectly from the cork.
3) Put down a thin film of "The Right Stuff" across the full length of the ends with a little extra in the corners. Main goal here is to fill in any imperfections in the block and get something the cork will adhere to.
4) I placed the cork seals down on the thin film and worked them into the precise position with extra attention again to the corners. Note, I was careful not to get RTV on the top side of the gasket.
5) I then placed cellophane (sandwich wrap) on top of the cork. The reason I did this is because I wanted to put pressure by temporarily placing the manifold on the cork gaskets to get them to tightly seat without having the manifold stick. I was so paranoid that the cork would flex in or out that I wanted to let the bottom side of the RTV set up overnight and then be able to pull the manifold off to verify the cork stayed where I wanted it. Worse case, if it moved, I wasn't starting all over - only restarting from the tear down point.
6) I set the manifold on carefully trying to get it as close to perfect as possible. I did not torque it nor even put the bolts in the holes. I chose not to do this as I didn't want to risk moving the cork gaskets around and I also didn't want to torque and then untorque the manifold gasket. I did not connect the hose to the water pump bypass as this would be useless since it was temporary and the sliding around may cause the gasket to move. I didn't install the distributor either. The theme is to set it straight down and try not to slide it. It doesn't have to be perfect since it is coming back off. It does need to put pressure in the right places on the cork. I did put about 135 pounds from my weight set gently on the top of my manifold to help put downward pressure on the cork and rtv.
7) In the morning, I came out and gently removed the weights and then the manifold The cellophane kept it from sticking in case any RTV happened to move torward the manifold. At this point, the cork is stuck very well, imperfections are filled in with RTV on the block and I can visually inspect all mating surfaces before permanently setting the manifold down.
8) Next I took more Right Stuff and put a finger full in all 4 corners being careful to get the tabs and inner seams sealed. I put a thin film on top of the cork all the way across.
9) I then placed the manifold down with little fear that as I aligned it and slid it around the cork would move. I used the distributor to center it and all the normal advice for starting and torquing the bolts down.
10) I then let it set up for 24 hours even though the Right Stuff says 20 minutes is enough.
11)I finished reassembly (I installed pushrods and rockers, adjusted valves and rest of assembly after it set up) I then fired it off. So far, no leaks. I hope I have it right.

As I said earlier, I know this is an extreme method and most mechanics probably scoff at this because there is no way you could make money doing it this way. But it was worth it to me to be a sure as possible to keep it from leaking.

I have pictures and more details if anyone wants to try something similar.

Thanks again for all the advice.