I am in the process of replacing Head Gaskets on 96 S-10 4.3, I have the manifold unbolted from the head but after soaking manifold to Y with PB Blaster I can not budge the bolts, have tried to use the handle of jack for extra leverage but afraid of snapping the bolts. Any suggestions? ( I do not have or have access to Impact)

 

Manifold bolts? Take it for a drive to get the engine nice and warm. Try the bolts while it's still hot(with heavy gloves). If that doesn't help try pouring water over the manifold to cool the bolts while the engine is hot. The water way isn't ideal, but it's worked for me in the past.