Originally Posted by cudaman1969
Originally Posted by topside
Try installing the tubes - especially the leaky ones - and plugs, without the top o-ring, and see if the plug isn't pulling the tube tightly to the head.
The o-ring could be masking a problem there.

Since the plugs are supposed to seat the tubes into the heads, it seems to me the issue is at the bottom of the tubes.
Take a careful look at the sealing area at the bottom: heads & tube face, plug threads.
Either the tubes, or the seating surface, or loose plugs/threads would be the culprit, I think.

I was going to say he might have the wrong o-rings and they’re holding the tubes to high. FHO guy has the correct ones


I honestly dont think the O rings are to big.

I put the spark plug in the tube, slide said tube into the valve cover, and screw the plug in by hand till it starts pulling the O ring into the valve cover.
It never really deforms the cover that I can tell, it just pulls/slides the tube / O ring down into the valve cover down so to speak,
spark plugs I feel are quite tight ( I did not put a torque wrench on them though. )

Im going to pull the tubes and spark plugs back out this weekend and double ck the seat area in the head with a flashlight . If all appears ok. I plan to put some kind of sealer around the hole in the tube and re-install .
This summer will pull the valve covers off and do the Milodon seals and planning to do valve stem seals same time