hello, i am new to this forum,, i could use some info,, bought a 96 4.0 elec. 4WD aerostar from ebay,, guy said it had "interment miss" didnt indicate major problem,, got it home, had it tested at ford dealer,, came up with bad head gasket,, my question is, how hard a change is that,, can a half butt shade tree guy do it? how much should it cost to do at a shop,, thanks for any help.. lenny rizzo