Check out V6 V8 V12 Car Engines with Full External and Internal Parts 3D Model Pack 3D model on CGTrader for $599. High-quality mesh by markos3d.
STL (Stereolithography, filesize: 761 MB), OBJ (OBJ, filesize: 638 MB), 3DS (3D Studio, filesize: 213 MB), C4D (Cinema 4D, filesize: 373 MB), MAX (Autodesk 3ds Max, filesize: 81.8 MB), FBX (Autodesk FBX, filesize: 921 MB), LWO (Lightwave, filesize: 763 MB), MA (Autodesk Maya, filesize: 391 MB), HRC (Autodesk Softimage, filesize: 887 MB), BLEND (Blender, filesize: 785 MB)