68 L48 Harmonic Balancer

[hrlyfxdl]

I've read through all the posts, and online info, I can find and haven't really found a confirmed answer. I'm looking to get an original harmonic balancer for my 68 Camaro. I'm having rebuilt and install a 1968 350 CI to put into it. I've looked to try and decipher and find a correct harmonic balancer. I've narrowed the part number down to 3896966 (I think), but as I search that part number I see many variations. Can someone point me in the right direction of what I should be looking for to differentiate a 67/68 balancer from a 69 (as far as I can tell by what I've read they are different even with the same part number). There are a bunch for sale on Ebay, but some say they cover from 67 to 74, some say 69 to 74, some say 67/68 and I don't know enough about them to know for sure which one I should seek out. Thanks for any input.

[william]

Whatever you do, don't use a '69-up balancer. For '69, Chevy moved the timing mark.

[hrlyfxdl]

That's what I was worried about, thank you for the notice. Any other info. on what I should look for in finding the right balancer, may a pic of the correct one, would be great. Thanks

[william]

If you can find it the November 1972 Car Craft had a great article about what to look for. Here's a pic from the article.

[bertfam]

The 3896966 is the balancer you want and the difference between the 67/68 and 69 balancer is where the index mark is located.

The 67/68 index mark is directly in line with the keyway and the 69 was moved 10 degrees counter clockwise (see picture below)

Ed

[hrlyfxdl]

And would this apply to balancers for the 350 CI, not just the Z/28 302? I found a multitude of 3896966 balancers but each one looks to be offset as described and not center with the Keyway. I did find one 7173 balancer, but the seller says it's for a 302, and it's the only one I could find with the timing line centered with the Keyway. Argh.....gonna be a tough part to locate I think.

[bertfam]

The part number (3896966) is 67/68 350 only, but the key way index applies.

Ed

[hrlyfxdl]

Ok, thanks Ed. I'll stay on the lookout now that I know what I need specifically. Thanks for the input. Hope this helps someone else down the line.

[bowtie68iho]

I'm resurrecting this older post because I think it needs additional research for a final determination on the index mark location.  I just removed my original harmonic balancer from my 68 L48 and took photos of both the front and back.  Plus, I took measurements. 

The measurements were as follows:
Diameter: 8 inches
Thickness: 1-5/16 inches (Incidentally, the new "1967 and 1968 Legends Judging Manual" on page 46 says the thickness should be 1-1/4 inches for 350 SS cars).

Contrary to what was said on this topic in February 2018, the index mark on my 1968 balancer is NOT in line with the keyway (i.e., similar to the February 21, 2018 00:21:44 post below by CRG member hrlyfxdl) and I haven't had any timing issues; however, the backside inner ring of the balancer is embossed with "3896966;" one of the three spokes on the backside has an embossed oval with "68" inside the oval...presumably for 1968; and one of the three spokes on the backside has an embossed "F"...presumably for F Body??.  My search of various 1967, 1968, and 1969 Chevrolet parts manuals shows 3896966 as being only for "1967-68/350 ENGINE - WITHOUT PULLEY."  The parts manuals do not show this balancer as being applicable for 1969 Camaros.  I included a copy of just one of the Camaro parts manuals to illustrate my point.

Any follow-up discussion on my findings would be greatly appreciated.

Bernie

[Stingr69]

Responding to the above post - Cast number on the hub is not the number to use as the hub itself will be commonly used in other non-Camaro applications.  The stamped "2222" number on the outside face of your damper is the number to reference.  Long version of the number is "6272222".  That part is a "69 and up timing mark. The photo does not look like a '68 production line damper.  I don't know how to read that date code.

The keyway on the SBC crankshafts are in line with the #1 and #6 crankshaft throw so that does not vary.  The timing mark on the damper varies and needs to match with the timing tab you are using so they are a set on any application.  The damper mark and tab zero are in different locations for different chassis applications due to needing to see the timing marks in service. the factory '68 damper/cover timing mark should be lined up 2 degrees off the crankshaft keyway centerline.

You can try to find a 50+ year old production line damper to try to use or just a common aftermarket replacement damper.  There are also reproductions now of the '69 and up "2222" part, but I have no experience with those.  I would not go that route personally as aftermarket replacement dampers are a better value.

As long as the damper has a sharpie mark where the zero on the tab lines up when the engine is at true top dead center you are golden.

[bowtie68iho]

Thanks, Stingr69!

The multiple coincidences with the embossings hinted at my balancer being correct...I'm guessing a previous owner installed my current balancer.  Anybody have for sale an assembly line correct balancer for a Feb 29, 1968 engine?  After your reply, I'm guessing that I'll also need an assembly line correct timing cover too.

[Stingr69]

..Or just go with the '69 and up damper and timing tab.  GM makes an inexpensive bolt-on tab for the '69 and up 8" damper. #12342011 about $14 or so.

[bowtie68iho]

The embossed date code on one of the three spokes was "22" presumably for Julian date of January 22?

[cook_dw]

Is your timing cover the original?  Can you make out the stamp date?

[bowtie68iho]

My car and the engine are several states away from me at this time so it'll be awhile before I can determine the timing cover date code.  Regretfully, I did not document that date code in my vehicle's files because the orange paint was so thick it obscured the date code...I would have to remove the cover and media blast it to get the date code.