Need some help

[72gmc350sbc]

So its been awhile since I've been on here, but Ive gained so much from all of you, thank you. I got my truck all put back together and up and running. I drove it for about 2 months until I passed a car one day. When I got around the car the truck wouldnt go over 25mph and it would bog down when I gave it gas. Not sure what happened, it will start but sounds like its only running on about 3 cylinders... I do know that the ceramic manifold gaskets were crushed, if that would make a difference? Anyone have any ideas?? Thanks guys.