The "balancer" really isn't. It's a harmonic frequency (vibration) dampener. Stock Mk IV engines did have balance weight on them but no one uses that configuration in anything high performance.

hence harmonic balancer!

But the balancer part is a misnomer. It doesn't add balance to the reciprocating assembly, other than the MK IV 454.

I you wanna get technical I think the correct term is harmonic dampener......

And yes, it probably doesn't hurt to make sure the dampner is balanced though.... kinda part of blueprinting...

There was an earlier thread which discussed "Dialing In The Bell Housing". Discussion included offset dowels for the engine block to bell housing,tolerances (courtesy of Mark Bam) and procedure. (I looked for the thread to no avail)

The math demonstrates importance of dialing in the "Bell Housing" even with a lite flywheel. Importance is amplified as the flywheel is heavier.

The procedure is simple,but requires patience. One needs a magnetic base dial indicator,torque wrench, sockets and rubber hammer.. The objective is to CENTER the flywheel,drive plate and bell housing to crankshaft centerline. The mag indicator snaps onto the flywheel and measures against the quality crank flange. Then,rotate the crank and shift the flywheel as required to find the minimum run out. Once CL is found,apply the lock tite and torque the fasteners. (It is assumed one will torque opposite to opposite,starting with a lite torque setting.) Next, the drive plate will be located by snapping on the mag indicator and again measuring against the crank flange. A goose neck will be required to get the indicator arm through the driveplate hub and reach the flange (a pilot bearing may make this easier). Once the flywheel and drive plate are centered, the mag indicator can be snapped to the drive plate and the indicator will measure against the bore or opening of the bell housing. In the probable event the bore is out of alignment,offset dowels will be needed for replacement of the factory furnished dowels. The offset dowels can then be rotated until the bell housing bore is within tolerance relative to crankshaft centerline,as the crankshaft is rotated.

Trivia points:

1. Flywheel and Drive Plate should be machine balanced once removed and prior to initial installation.

2. Hitting the Flywheel or Drive PLate with a metal hammer may cause an imbalance. Use the rubber hammer gently.

3. Grease on the splines may adversely effect the Drive Plate disks.

4. Subject to Horsepower,loading and shock, the Drive Plate Hub and Springs may require periodic maintainance.

5. When the Flywheel and Drive Plate are NOT centered to the crankshaft, they become similar to an automobile tire that is out of round and/or out of balance. When the Bell Housing is not centered, the transmission input shaft is forced to turn with a side load.