69 Z-28 Balancer question

[69L78Post]

What's the correct part# for a 69 302 harmonic balancer? A friend of mine is collecting parts for his Z and is wondering if he has the correct one or not.

Thanks,
Barry

[Mr.Nickey Nova]

Part# 3947708 and is 8" in dia.

[Salvatore]

Post a picture and we will tell you. The timing marks are offset. Assembly line balancers are different looking than the NOS or over the counter part.

[69L78Post]

Thanks Mark and Sam. I'll see if I can get Al to send me a picture to post.

[L78steve]

[ QUOTE ]
Post a picture and we will tell you. The timing marks are offset. Assembly line balancers are different looking than the NOS or over the counter part.

[/ QUOTE ]
Offset from what?

[John Brown]

The 69 timing mark is offset from the keyway groove. The 68 and earlier balancers have the timing mark directly in line with the keyway.

[Fast67VelleN2O]

Here is an original 1969 7708M assembly line installed balancer.

[Salvatore]

That is the one. As long as the timimg marks are offset. Looks like a real nice balancer.

[L78steve]

[ QUOTE ]
The 69 timing mark is offset from the keyway groove. The 68 and earlier balancers have the timing mark directly in line with the keyway. [/quote
So I have this correct in my head, The 68 and earlier crank keyway is cut pointing towards #1 TDC and the 69 up crank keyway is straight up at #1 TDC.

[JohnZ]

[ QUOTE ]

So I have this correct in my head, The 68 and earlier crank keyway is cut pointing towards #1 TDC and the 69 up crank keyway is straight up at #1 TDC.

[/ QUOTE ]

The hub and keyway didn't change. The location of the timing index line on the inertia ring changed. The timing index line on the ring prior to '69 was directly in line with the keyway, and in '69 it was moved 10* counter-clockwise from the earlier location.