I have a vibration at around 3k rpm's. It does it all the time. I can kick it out of gear and it goes away. The motor is a 383 built by McClure racing, runs strong as hell. I run a centerforce clutch with steel flywheel. I am kinda leaning towards a new balancer, it has a cheap looking one on it. I thought maybe putting a Rattler on it. Any ideas? Anyone going or had similar problems? If someone can help me with this problem there will be a free, half full Miller lite as a nice reward!!!!!!!

Need more details,..does it vibrate while driving down the road?...or can you duplicate the vibration while she's in neutral?

You say the vibration goes away after "kicking it out of gear". If this is the case,..remember, the flywheel and pressure plate are still turning, in or out of gear, and probably not the cause.

I'd dismiss the balancer (or damper as some call it) as the culprit as well based on the info so far.

I've fought a few vibration issues myself.

it will vibrate in neutral at 3000 rpm....underlight load. If I give it more throttle it will ease up. Also, when I am above 3200 rpm's it will go away. I have ruled out wheels/tires and drive axle. So, if I am driving or sitting in the driveway it will vibrate at around 3000 rpm.

When you built the engine, was the balancer and flywheel incuded when the engine was balanced?

If not,..what crank did you use,..an externally balanced GM 400 crank?..or an aftermarket internally balanced crank?

There's a chance your flywheel or balancer is the wrong part for you crank, but I'd guess it would vibrate much more than you're describing.

Here's another thought. Is your radiator fan missing any blades or parts of blades? This will certainly aggravate the engine balance.

Let us know.

I will call mcclure and find out all the details...I have an electric fan and the car and the water pump/crank/alt pulleys are billit aluminium. My gut tells me it is the flywheel..............

Oh, I am with ya on this topic. I have spent over 10K chasing vibrations in my '68 Camaro SS with 454. I even went so far as to have engine internally balanced (was external balance) and that helped some, but it still ain't as smooth as it oughta be.

I was running poly mounts, but am now changing them out for stock mounts. Plus I am really gonna check pinion angle carefully this time (I got it all apart again).

My other suspect is headers. I'm running Hooker Super Comps, which are REAL close to chassis in numerous spots. I dented them to get clearance, but damn, they are close. I may switch to smaller header.

This is my fifth time for engine out. First two times, engine shop had balancing wrong. I went to balance shop and watched them on the third attempt, and they had to add over 100 grams to get balance right!!!!!!!!! It's a real shame, but you can't depend on anybody to get it right the first time.