Nope, 250 engine is attached up by head. 500 engine is attached at lower crankcase. Custom mounts needed (30-minutes to cut & weld bar-stock, tubing will be lighter). If you look at picture above behind radiator, you can see the mount. It's flat bar-stock and bolts to engine just above water-pump (shiny bolt).
You'll also need to weld up custom exhaust. Looks like one above used factory header pipes combined into 2-1 custom exhaust with maggot muffler.