G'Day

I own a 1986 744GL which has recenty blown its motor due to a head gasket blowing, I have a spare motor out of a 1984 244GL, but this has mechanical injection, I have checked the blown motor and it is seized solid but the head and fuel injection are fine. I am thinking about "retrofitting" the fuel injection head and inlet manifold to the mechanical injection block. I have talked to some mechanics an was told that the heads were the same but the only difference being the size of one oil galley. But if this fails I will leave the mechanical injection head and manifold on it and put this motor in as it is with the 740 4 speed auto behind it. If any of you have tried this and sucessfully/unsucessfully done this conversion, tell me about it!