Thanks for the updates; an interesting case study and follow up.

 

I was circling back to this post, after letting it rattle around in my brain pan, but Larry beat me to my conclusion.
I agree.
Simple as probably setting the heads in a fixture in a vertical mill, and trimming the intake pads as needed.
Piece-o-cake.
Scott

 

And the saga continues some more...
So I was never ever able to get it to idle properly. I finally pulled the front head and started measuring. I set the head gasket surface on a piece of 3/4" thick glass and measured down from the rocker surface through the stud holes and all measurements were within less than one thousands. .0008". I then determined the angle from the head gasket surface to the intake surface and it was 90 degrees. Then I made some brass dowel pins with a snug fit for the dowel pin holes in the head. Using a straight edge against the dowel pins I figured the intake surface is 20 degrees from 90 or 110 degrees. It's been my experience that Harley likes using easy whole numbers in it's designs. I could find nothing wrong with this head so I went to the rear head. Here I checked the gasket surface to the intake with a square and found it was not 90 degrees! WTF? I put it on the glass and found the gasket surface out by .0025". I set it up in the mill and took the smallest cut I could to clean it up and got it at .0008" also. This helped but the intake surface was still not square with the gasket surface. I then took both heads and mated the gasket surfaces together with the dowel pins lining them up. With a 4" straight edge across the intake surfaces I was able to get a .003" feeler gauge under it at one end of the surface and .008" on the other. So the surfaces are not only not the same height but not the same angle. I'm hoping this is enough of a difference to affect the seals. I will be setting it back up in the mill on a rotary table and indicating the dowel pins and rotating 20 degrees and taking a clean up cut to make them the same. I sure hope this cures it as I can't think of anything else. Thanks to Kirby and Hillside for helping me think outside the box!

 

"RCH", as in "red c**t hair"? Yeah, they`re the thinnest.

Naw, you got it backwards. The RCH is thinner.

 

RCH is thickest! .006" Brunette is .0045 Blond is .003"

 

While I'm having trouble understanding what you are saying exactly, I suspect that you are really chasing off the wrong direction..

From what I read, the mating surface for the manifold is off a few thou from mating up with the manifold.. This should not be an issue. As long as the 2 spigots are close and the flanges can support the manifold well enough to set them in line with the ports, you should not have leaks. They only have to be close enough.. You can have 0.010-0.020 difference in gap and not have an issue.. If you start getting above that the seal can squish between the manifold and head then leak.

I suspect that you have something else going on.

Are the heads 06 up heads?

Did you change the flanges if you they are? Are they straight?

What is the diameter of the Ramjet spigot?

What manifold seals are you using?

What carb?

After the manifold flanges are 1 turn from tight and greased, can you move the manifold up or down from where it is going to sit a couple degrees?

Are the manifold bolts hitting the manifold and pushing it to one side?

Have you looked for cracks in the manifold?

How well is the carb backing plate spaced to the head?

 

That has been my experience as well.

 

2002 heads
New manifold
In place it will hold 20 inches of vacuum with the both intakes closed. I'm thinking that the amount of vacuum the engine actually makes is more than 20 and starts to leak. The problem is only at idle.
I only used the RamJett to check alignment.
I've used stock, blue silicones and black ones with the imbedded washer.
3 carbs, Stock, Mikuni 42 and a Bob Wood CV
Manifold is fine, nothing hitting, it's free and the backing plate is a K&N but I've also tried a stock backing plate for the CV's.
I believe that machining the intake surfaces will help with alignment because no matter how careful I am assembling the intake and carb it always want's to pull to one side. While I have it all lined up I'm taking a skim cut off the backing plate mounting surface just to be sure it's all square.
I put 156,000 miles on my old 91 FLHS and never had any vacuum leaks. I also have a Buell Ulysses with almost 50,000 on it and had some problem getting it sealed but once it did it's been great for many years. I've done conversions to CV's on friends bikes and none of them leak either so my method of lubricating the seals and tightening them down a little at a time and evenly has worked well over the years, just not on these heads.
What sucks is I took my heads to a builder for porting etc. and he sent two sets of heads in for the same thing. Mine did not come back first and I had a big trip planned so he gave me the other guy's heads since he wasn't in a hurry. I've had problems ever since. That's why I'm trying to make everything spot on to eliminate any errors I can think of.
The fact is I agree with you totally, I should not be having a problem.

 

Just curious.. How are you determining that you have in an intake leak in the first place.. Then how do you verify.

 

Are you 100% sure they are a matched set of heads from the same displacement engine?