360 Magnum vs 340 mild street build - my experience

Do it, but get the 5.9 crank drilled for the 273 trans (manual or auto) and get the proper balance plate. Youll have to fab the new headpipes and MAYBE clearance the steering linkage but youll almost double the HP. You can even put the old 5 bolt LA valve covers on the 10 bolt magnum heads
Awesome