Yes it is handy to draw knowledge from someone much more experienced like Chris, this one has a smaller pulley diameter than the old falcon one so i'm not revving the guts out of the alternator. Cheap insurance against the risk of losing a flywheel and ruining a crank.

In the time that 'The Boss' has been using a harmonic balancer, he has not had a single flywheel problem at all. Prior to that, ... well he still has the busted parts laying around.
To say that flywheel problems have completely evaporated since using a balancer would not be an overstatement.

I understand that you have a new engine built with some goodies from 'The Man from the West'

Love to learn of the new power in the land & to show you the goodies that he got for me. You'll love 'em.

Did you ballance it with the recirpocating bits or just bolt it on? I'm interested in how this helps since they were not on the motor from factory, also what are they worth?

The engine's fully balanced, the balancer itself was not balanced, but i did check its' static balance on a knife edge and it was pretty much perfect. The point of having the balancer is to dampen out the torsional vibrations of the crank as it loads and unloads in the twisting direction. It pretty much eliminates flywheel bolts loosening, plus would reduce fatigue in other bottom end components. It cost me $350 from ross balancers in blacktown, cheap insurance in my view.

interesting stuff, i debated for ages about putting an aftermarket underdrive crank pulley on my sr20det and ended up not wanting to risk it with some negative talk about it.

As i was pulling the flywheel off a 1000 engine yesterday i noticed it had tabs that fold up to stop the flywheel bolts from undoing. Your engine setup looks the goods, i'm just trying to understand what a harmonic balancer actually does and at what point you need one

A harmonic balancer is like a small flywheel at the front of the engine, except that it is mounted in rubber or other elastic material & is integrated with the front pulley. As the rotating crank accelerates & slows during a single rotation, or as Aiden correctly put it "loads and unloads in the twisting direction", this 'little flywheel' either lags behind the acceleration, or over runs the deceleration of the twisting/rotating crank & it can do so because of its flexible mounting ring. This has the effect of damping out the worst of the sharp changes of rotational velocity & as the name suggests, it helps to balance out the harmonic frequencies in the crank & in so doing it can save the engine from a nasty incident at speed.

In the A series engines case, it either dampens the frequencies that cause the flywheel to move on the crank, or it moves these frequencies to an RPM level low enough to not be a problem, or high enough to be out of the normal range of even race engine operation. [or all of the above]

Well, that's how it was explained to me when I was a young tradesman. I just hope that it's right.

As a few of our number have learned, to their cost, that when an A series shears off the flywheel bolts it also frequently suffers from a cracked front pulley. In a worst case scenario the crank, flywheel & pulley can all be lost & replacing these bits is a pain both in the wallet & the backside.
If a harmonic balancer can save this from happening then it's a good investment.

This is a link to the Ross balancers website It's well worth a look.