Vice grips were worthless for me. Heat, 1/2" breaker bar with 1/2" 6pt socket, and the ones that didnt wanna come out got the sawzall. Cut in between the manifold and block. Then I used a 7/8 sleever bar to pop the manifold loose. The passenger side was a btich kitty. No shame here, took me two.hours of cussing, heating, spraying pb blaster, and breaking sockets. Lemme explain: the 1/2 socket would round the hex bolts off when you really get on it with a breaker bar. So id take a 12mm 6pt and pound it on with a 2lb hammer and then put the breaker bar on and pull as hard as I cared to. Broke three craftsmans, the evercraft(napa house.brand) took it and is back in the toolbox. Keep that in mind,lol.
Once I got the pass.side.manifold.cut loose I grabbed a pipe wrench and twisted the four rear bolt remnants out and wound up with one bolt shank rusted solid in the manifold. I dont really have a good.picture of.that, sorry. I plan to take it.to the shop tomorrow and drill it out.
In a humorous twist, I got the drivers.side manifold off in under ten minutes. I heated, sprayed, and broke them.all loose. Grabbed my makita impact driver and spun them out. Done.
My take is that you'd have to be.crazy to attempt this in the truck. Especially when one.breaks or needs.cut.