They are just long bolts so you are correct that if you cut the head off you
can slid the manifold off. I'd be tempted to just saw or grind it off.
Then you will have plenty of bolt shaft to work on with vise grips. After
that you can soak it with wd40 for awhile if you need to. Just give it
another shot every day or so for a while. Stainless marine has some nice
aluminum manifolds with ss risers for sb chevys if you're interested in
aftermarket stuff.

"ToneJohn" wrote in message
...
I have a Mercruiser 5.7 350MAG. I'm planning on replacing the exhaust
manifolds and elbow's at the end of the season. Anyone have any tips on
doing so? The only problem i forsee is one of the bolts trhough the
manifold into the block is very rusted to the point where i don't even
think i can get a grip with the special socket set. My thoughts are
heating it and then removing the head and slide the manifold out then work
on the bolt into the block... Any suggestions ? ? ?

Thanx...