Can i use the intake and exhaust manifolds from a 305 on a 350 switching engines in 1987 gmc pick up?

-Yes , very compatible. If the years re not the same, only thing is egr valve and may have to route your cooling line. No big dealYou should be fine with the ones that are on your truck now. I dont believe the 305 and 350 manifolds were different. I know they will bolt up and the flow difference between the engines is not that much.