Welllllll, !!!, I suppose lots of GM parts are outsorced now and as long as it fits the crankshaft snugly the timing mark is in the right place. Check this by winding the motor over by hand to 1 TDC by using a piston stop in the sparkplug hole, you should see if the 0 on the timing marker lines up with the line on the harmonic balancer.

2 more points make sure that you have an internally balanced balancer, that means no counterweight on the balancer.

Is it an 8 inch or a 63/4 diameter balancer ?

Just a question totaly different from all this what kind of transmission are you running and what was the car type again ?