I am about to have my 3.1 balanced. It has a 981 crank which if my feeble memory serves me correct it is internally balanced and the flywheel or flexplate used will be neutrally balanced but what about the harmonic balancer? Can you use the stock balancer from a 2.8? Pretty sure you can. I have to have this all balanced as the pistons I'm using are 3.1 flattops. Anyone here could you please confirm my thinking as being accurate I do not want to blow this up after running for 5 minutes.

Thanks

Balancing Rotating Assembly

Everything that rotates except the torque converter.

Balancer is optional but always include the flywheel.

I'm doing a 3.1 from a 2.8, and as far as I know the harmonic balancer is the same. You might want to make sure it is in good condition.

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87 Fiero GT (Rotrex Supercharger)
Rebuilding Engine! Check Website under FIERO REBUILD!
WWW.angelfire.com/pa5/davidfiero/

The harmonic balancers for the 2.8L, 3.1L and 3.4L (pushrod) are all the same. The only difference is the timing marks. The Fiero timing scale is to the left of the water pump and all others are to the right of the waterpump. The DIS engines don't have marks. (I think)
GM performance makes a stronger balancer, but you need to scribe your own timing marks for the Fiero engines.

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Happiness isn't around the corner...
Happiness IS the corner.

quote Originally posted by 84Bill: Balancing Rotating Assembly Everything that rotates except the torque converter. Balancer is optional but always include the flywheel.

yeah. what he said.