Engine Vibration 3k RPM

T56MaxTorq said

If it’s worse in neutral, it is not the driveline or the rear axle.

check ignition timing at point of vibration

what are the motor mounts condition? All 3 ok?

Is the exhaust secure?

How about the harmonic balancer? What’s that condition and age?

If the engine received new pistons but didn’t get balanced (which is sometimes ok to do) than it may vibrate like this all the time at that rpm.

Click to expand...

I wouldn't say it vibrates worse in N, I would say the opposite. Its worse when driving at that RPM.

All three mounts are new and in good shape.
The exhaust was just welded up (Summit kit w/clamps)
The balancer is new, but I would like to recheck the timing to be sure it hasn't jumped.
I can't remember if the engine was balanced when it was put together as that was 8+ years ago. I do remember KB hypers +.040, the crank and rods were what came with the motor (stock stroke). It was a very mild build as I wanted to have a nice driver.

What is the best way to verify engine balance? Does the motor have to come out and take apart?