coolant in the intakes manifold

Hi all, firstly thanks to all that helped me find a new cylinder head for my 6 cylinder 2.4 petrol 1991 lt 28. after many many hours and much expense I managed to get it all together however came across a rather curios problem. After I filled the coolant system I was double checking a few things and as I was turning the engine over by hand I got covered in water from the plug holes. Seems the cylinders had all filled with water !!!!!!! the coolant is filling up the inlet manifold then the cylinders, why ???? what have I done wrong, why does a pipe from the coolant have a direct route through to the engine inlet? I imagined the pipes may be routed through channels in the inlet manifold to warm it but I don’t understand this at all. I need to get the van running and moved by next week or its going to the scrap yard as ive nowhere to keep it after this week. I’ve spent over £600 and a good weeks work on it but I think ive had enough now. The van is in beautiful condition bodywork fantastic I just want to get her going mot it and then pass it onto someone who will use it, any help it goes without saying much appreciated thanks matt.