I had a devil of a job removing the carbs, I had to chisel through the insulator to free it from the studs.
I have tried to remove the manifold, soaking/ heating but it is solid. Is there a need to remove it ? I am hoping not to machine the head . I would rather leave it than break it.
Yep, corrosion of steel in aluminum, always a problem with these.
I would remove it. There are water passages in there that could be gunked up.
I was able to remove all but one stud by the double nut method. For that last stud I removed the core plugs at each end of the manifold, ran a steel rod through it, then suspended the manifold and head by this rod, so the weight of the head was pulling down against that stud. Then Kroil penetrating oil and heating with a propane torch every day for a couple of weeks and tapping on the end of the stud and it eventually moved.
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I’m not sure how to link it, but if you use the search button for “XK120 Inlet Manifold Removal Quandary”, you’ll then find my experience. Not good. Avoid it if you can. The studs swell with rust from moisture that bleeds away from the surrounding water passages.
I’ll second Robs recommendation I’m afraid, best to get it off to make sure it’s serviceable. Perseverance, penetrating oil and heat are your friends.
If you can get the relevant stud area immersed in diesel for a few days that would help. A bit of heat might help but I’d be careful on an ali head.
Alternatively you could get the machine shop to do it. Surely, having got this far in, you’ll be replacing valves and guides?
I will keep at it.
I won’t be replacing the guides as a matter of course, let’s see what they are like first. Like all things XK , I have had strong advice to skim the head and strong advice to avoid it. I think fitting new guide requires the head to be heated so would probably require a skim
got a good one apart, but found the valve seats were badly recessed
Surely the advice for skimming would be to check it properly first, including deep scratches and corrosion, and then skim if necessary? You wouldn’t do it as a matter of course, each head has only so many skims in it. Unless, of course, you want to raise the CR - but why would you want to do that?
A 50/50 mixture of acetone and automatic transmission fluid (ATF) makes an excellent penetrating fluid. Removing all the studs would sure be a good start to removing the manifold.
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Good progress, 2 remaining, but still firmly stuck. Not enough thread to double nut the last 2 .Thinking about welding on s single nut.
Are you aware that the 8 carb studs also must be removed?
You might try a stud extractor tool.
And apply the torch heat on the manifold circling around the stud. Do one at a time, then let it cool down before going on to the next.
“Are you aware that the 8 carb studs also must be removed”
Mmmmm …I knew that 
All out now bar one carb stud I have broke off flush , pretty disappointed in myself. The manifold is loose but the broken stud will not wiggle off. I think I will have to drill it out.
As stubborn as the manifold and head studs can be, I’ve never found the valve guides difficult to remove.
If you have enough of a nub left on your broken stud, I have had good success welding on a same diameter bolt with a mig. Grind a point in the new bolt, so you have room for the weld. The heat transferred into the broken one also helps a good deal. Surprisingly effective.
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if you dont have a good stub, weld thru a washer hole onto the stub, then weld a nut onto the washer
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It’s off !
Thanks for the tips. I did consider welding, but I had nothing protruding and as Mig is so hard it would make drilling more difficult. As the others had seized at the top I drilled down about 1/3 , heated and wiggled. It has wandered off a smidge but very pleased
Tony, good tip, I’ll hope I don’t have to use it!
Good work Jim, ain’t this fun!
Yep , it would be boring if it was easy .
Are replacement studs available in stainless, maybe??