8 to 10 hrs labor to change '225' head gasket ?????

so my mechanic is saying 8 to 10 hrs ...to change head gaskets ,swap out exhaust bolts ,and put new exhaust manifold and all back together..1969 225 slant six..at $82 an hour......is it really that big of a deal to take the head off and replace the seals @ gaskets...what do you guys think...