I currently have a 1985 4x4 K5 Blazer with atired 305 small block and a 700r4 tranny. What would I need to swap a 400 SBC from a 1977 Blazer with a TH350 into my truck? I only want to swap the engine. Are the flexplates different? would it be a straight bolt on to my tranny? Thanks in advance for the help.