For the price of $40.00, it was a no brainer for me, to replace my crusty intake manifold with a NOS unit from Italylovers, off ebay.
But, removing the fragile thermostat housing proved difficult.
Even after soaking with Kroil for over a month, it wasn't going to budge.
So, Still treating the casting like glass. I got drastic to day. and got the hacksaw out
Then chucked the assembly into the lathe by the studs and carefully drilled out each one.
The rusty studs would not give up their grip, until they were drilled completely out.
Success After spending an afternoon in the garage