After getting front wheel vibration at 65 mph. I switched the driver side front to the rear, moved rear to front. Vibration gone .
Question is whether rear wheel balance is critical ?

As you've noticed the rear is not as critical.

Front suspension has more degrees of freedom than the rear. Rotational imbalance in the front can more easily set up an oscillation that you can feel. You feel it more readily in steering wheel by virtue of the direct connection to your hands. Your hands and fingertips are the most sensitive part of your body. Cross-car osciallation in the steering system is damped only by interal friction of the steering system.

Rear suspension can still set up an oscillation in vertical direction. However, now you have dampers acting in that direction. Likewise your -ometer isn't nearly as sensitive as your hands so you don't notice it as easily.

You can still have rear wheel imbalance that is nasty but it will rarely be as noticeable as on the front.

Thanks for that !

Still a good idea to have balanced wheels on rear...a bad out of balance can contribute to suspension wear.

Good point. Will have both re- balanced….

Jim, if the previous front wheels won’t balance well, probably one or both of that front wheels has bent.

Both fronts were recently balanced at Grand Prix in Costa Mess. I think one or more of the balancing weights came off. Some of the road repairs can be felt up through the steering wheel.

What year is your car? Its more critical on the early (pre 1972(?) ) cars without the hub centering ring on the front to ensure the wheel is tightened evenly and is as centered as possible.

The 914 is a ‘75; however, the front hubs are custom billets that Brad Roberts sold. Not sure whether they a provision for centering