After some time spent diagnosing a ticking / squeaking sound coming from my 403, I found my harmonic balancer to be completely separated. There are 2 holes drilled into the outer edge of the balancer from when the engine was balanced by whoever rebuilt it. My question is whether or not I can simply just replace the balancer without throwing the engine out of balance?

 

Yes

 

cool thanks. Are all factory original balancers the same, or do I have to order one with the exact same part number ?

 

The drilled holes are there to balance the balancer.

 

As long as it is factory used or a rebuilt original, it will have the same balance. There are aftermarket balancers with add on weights, more pissing around than neccessary.

 

Go with an OE or factory replacement (I was still getting them from GM dealers in 2001......) and just bolt it on. Post a parts wanted ad on here and someone will offer one.

As mentioned, aftermarket ones do not necessarily have the same weight offset, so it's a bit of a gamble to switch to those. I know ATI and Pro Products both have more offset than stock.

 

You can have that one rebuilt too.