AMC Harmonic Vibration Damper Listing

 I need to MAKE a 4 bolt balancer that will work with my 290 for the accessories from my '82 Honcho.   

Hi Dan!

Edited by carnuck - Apr/22/2012 at 10:21am

I guess I should've been more clear. I meant to ask if the newer balancers would work on the older cranks. Especially ID and belt alignment. We have Perpetual balance here for the matching (they balance turbine aircraft engines as their day job)

Now I get your question.

All AMC genII and genIII V-8 crankshaft snouts are the same OD so all the balancers from the 290 to the 401 will bolt right on. The pulleys and water pump however are different due to the greater balancer depth on the later engines. You will need to get a full pulley setup, including PS and alternator pulleys plus a 72 and up water pump and all will be good.

BTW, I've seen where some folks shim the old style pulleys with washers but that is kind of hokey and not a great idea due to variances in washer thickness that can easily cause pulley wabble or misalignment from one pulley to the next.

Lots of guys on here, myself included, have bins full of pulleys and I am sure you someone can come up with a set if you can't find them locally. The biggest issue however is water pump shaft length so be sure to get the water pump for 72 and above which is mostly all that is available anyway.

amx39068 wrote: SC397 wrote: '70 390: #3196925 (same part number as a '70 360 but balanced differently) This makes no sense to me. If I went to the dealer in 1978 and asked for part# 3196925 how would they know if I wanted the 360 version or the 390 version? So real question is are we talking about a casting number or part #

Dan is correct.  When I worked at the Kenosha plant I researched this.







Clearly if you ordered a damper assembly for a 1970 390 or a 1970 360 you would receive 3196925.  It would have the imbalance shown in note 4.  This would not have been as accurate as the factory balance on the engine but I suspect this was done many times without imbalance problems.

When the crankshafts were redesigned for the 1970 model year they were designed with the same imbalance.  Inspection of used dampers may show a trend that 360 dampers were balance drilled at the factory alike and that 390 dampers were balance drilled alike also but that would point to trends in the crankshaft balance not a design difference.

Looks like Rick is right too.  I will fix the wording so that it is more clear.