Having some vibration issues with my 331 and have a feeling that it's the balancer causing me the grief. I have a fairly noticeable vibration and light miss at idle. I initially dismissed it as the rough idle characteristics of my camshaft, and I do have poly engine and trans mounts, but it's just not running as smoothly as I think it should. As I get into the throttle (in neutral) the vibration seems to worsen. To the point where I can really feel it in the shifter by 4,000RPM. If I get on it under load out on the highway, it'll shake my shifter to the point it's rattling against the shift stops. I've changed clutches, driveshaft (switched to an aluminum unit), adjusted my pinion angle and it doesn't seem to make a difference. The engine only has about 3,000km on it and the rotating assembly was balanced to 28 oz. by CHP. I've got one of their non SFI aproved Pro/Race balancers and their billet steel SFI approved flywheel. You don't often hear of new flywheels going bad.....but balancers on the other hand seem a little more common. I knew I was taking a chance with the Chinese built balancer in the first place, but it still seems to be built of a far higher quality that the stock cast ford units. The timing marks seem to be in accordance with my timing light. I don't see any cracks, or leaks on the balancer. I can't however think of any other way to definitively test it? I plan on calling up CHP to bend their ear on the subject a little and enquire about the possibility of an exchange, but considering the trouble I had during my initial dealings, I'm not feeling overly optimistic. If I can't get any warranty satisfaction from CHP, I'm looking into a replacement balancer at a reasonable price. I see the Pioneer Automotive brand thrown out there a lot and wondering on everyone's thoughts on them? Are they a decent replacement balancer, or am I going to end up scratching my head again? And if not the Pioneer, then what? I'd like to stay with an elastomer style balancer, that won't break the bank. Ford was able to keep these engines balanced for 20-years with a junk cast unit, so there's no reason I should need some high dollar race unit to do the same?