IDK what book says gotta be at least 6-8 hr but I replaced the the gasket and few of the manifold bolts on one of my old firebirds and the manifolds on my old F150 it wasn't bad and I came from NY so rusty lol also it was straight 6 in V8 engine bay so made for lots of room IDK about your vehicle I know its tighter in my 10'.
But check it might just be the gasket see if they sell one does it make a difference and you hear it more cold or hot?
if it is gasket water down the bolts with a perpetrator soak em with the likes of pb blaster or similar every other day for a week use only 6point sockets and wrenches that's what I did and all except 3 slid out like butter loosened the upper exhaust pipe connection and reversed done in a afternoon
But check it might just be the gasket see if they sell one does it make a difference and you hear it more cold or hot?
if it is gasket water down the bolts with a perpetrator soak em with the likes of pb blaster or similar every other day for a week use only 6point sockets and wrenches that's what I did and all except 3 slid out like butter loosened the upper exhaust pipe connection and reversed done in a afternoon
