Rusty exhaust bolt removal help needed

[GMTG]

I have a 74 Valient with a 318 in it. As the pushrods vary from bananas to "S"s, I figure I better pull the heads and see what damage there is to the valves and pistons.
The bolts on the exhaust manifold scare me. I do NOT want to strip or snap them. I know I should soak them with Liquid Wrench for a couple of days, periodically tapping with a hammer.
Should I use a steady slow pull with my breaker bar, or would it be better using an air impact wrench for the sharp, sudden shocks? Also, should heat from a torch be applied?
Any info would be greatly appreciated.
GMTG

 

[mrspeeddemon]

if the bolts gonna break its gonna break, but the impact might break it easier! osak them and hope for the best, I would even suggest against a breaker bar- because as the name suggests it breaks things! Try working it loose with a ratchet back and forth,back and forth, :drinkers: ect, ect.....