Hopefully as cTaylor has mentioned you won't have to remove the head. A new head will cost $3K! Rebuild heads are difficult if not impossible to find . Having the head rebuilt is expensive $2K-3.5K. If you end up ever needing to have that done there are many many other things that you should get replaced at that time.

BTW I'm still fiddling with my Zenith carbs!! Yikes!!

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MB 72 250 M130.923 114.011 170k The Beauty