the timing needs to be retarded a degree or two, as it starts pinging a little bit at about 5000 rpm at full throttle. Also, it sounds like crap. It sounds like my brother's 390ci '74 f100 did when the exhasut manifold was cracked in half. I've got about the worst exhasut leak ever, I have to fix that. Other than those two little things, though, it's running pretty good 