i was able to let my intake sit for a day or so in a large rubbermaid of diesel fuel. i found out that a mixture of diesel fuel and paint stripper works pretty good too. gets gunk and paint in one application right there.

heads, piston&rods and stuff i usually soak in a rubbermaid full of purple power/castrol superclean type of degreaser. you can strain and re-use it for smaller things later, too.

diesel and a parts brush and putty knifes worked great on my similar looking crossmember.