He is correct.It's called half & half.
The hub and balancer is "0" balanced and it doesn't matter what way it goes on and the flywheel has a weight on it and the bolt pattern will only let it go on one way.
The holes are there to "0" balance the balancer.

 

Who is Doug Anderson?

 

Here's my opinion and experiences......The Doug Anderson info is 100% correct......GM did hot balance many of the motors on the assembly line making, (not all) but "many" of the LT1 engines not Zero balanced in the front like everyone usually assumes they are...a hub with no keyway with afterthought hot balancing was just one more of GM's mistakes on the LT1........Iv'e known plenty of guys that removed their factory harmonic balancer to replace it with a higher quality aftermarket zero balanced unit, only to then pick up a very slight vibration......Iv'e also known a few that did optispark replacement jobs and diddn't mark the hub when they foolishly removed it, only to have a pretty violent RPM dependent vibration after the car was put back together.....in all instances, trial & error fitting the stock hub & balancer at several different positions like those of a clock was enough to remove the vibration....this proves to me that their not all zero'd on the nose....IMO this is so monumental of an overlook on GM's part, that many can't even believe it exists http://www.automotiverebuilder.com/ar/ar99928.htm then go down to hub and balancer section

 

I know that my crank, at TDC, the keyway is @ 1 o'clock. I can't imagine that the crank manufacturers would make them all different but who knows.
With that being said the crank keyway would be a @ 1 o'clock and the hub arrow would be # 12 o'clock.

Mike

 

The trusty Helm's manual has the easy solution:

1. Get #1 cylinder to TDC (if the timing cover is off this means line up the cam/crank gear dots).

2. Install hub with the arrow at 12 o'clock (arrow is cast into the hub).

3. Balancer only bolts on one way so bolt it up (match its arrow to the hub arrow).

Simple and factory correct.

 

.....

 

So what's to keep the hub from spinning on the crank? I guess every time that happens you'll "feel vibration" and repeat steps 1 thru 3?
This thread is funny...

 

On the 3 H&C projects I've helped with all 3 with stock cranks were the same way.

I figure if you put the hub back on the way it came from the factory it surely couldn't hurt.

 

The only think that kwwps it from spinning is how tight it is pressed on and the serpentine belt is not that hard to turn. I keyed mine incase i put on a blower.

 

Why was the hub removed in order to put on an under drive pulley?

 

Surely, but how do you know it's still in the factory position?
You coming to any EFA events to get thy *** cracked?

 

I don't but when I switched over to Joes cam from the 306 the hub was in the same postion I installed it at. Might have moved since then that was almost 3 years ago dunno.

As for getting my *** cracked I don't know, maybe. I guess that means James and Chris are running again huh?

 

id also like to know the answer to this one?????

 

The hub didn't need to be removed in the first place actually. I didn't have a 3 jaw puller and my father in law mechanic who's never worked on an LT1 before took it upon himself to pull it with the balancer thinking it's all 1 piece. He's old school (65 years young) and didn't understand why I wanted to put a U/D pulley on in the first place. Not understanding what I was telling him, he removed it while I was at work. After driving it 500 miles like that I'm still a bit paranoid about it but it hasn't caused any vibrations at any RPM level fortunately.

 

Thunder Racing has a fix for this
you gotta pay to play