1972 350 Harmonic balancer help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1972 Jimmy · 01-14-2015, 09:47 AM

Hello all,
Need some help determining what is the factory correct harmonic balancer for a 1972 350ci in my 4x4 jimmy. I'm not sure on the diameter or thickness. If anyone has the casting or part numbers the would be great as well!
Thanks,
Eric

1972 Jimmy · 01-14-2015, 08:07 PM

Anybody???

davepl · 01-14-2015, 08:48 PM

Part numbers are all in the part number books. I will guess 12551537 but you'd have to look up your own truck.

I found 10 on RockAuto.com, so not to be "that guy", but Google first.

Long story short (more experience mechanics can correct me here if I'm wrong) the 350 is a neutral balance engine so as long as it fits your crank snout the only question you really need to answer is how much you want to spend.

You can pick up a Dorman brand new for $30.

You can spend $500 on a liquid-filled, SFI approved, turbocharged 3D version.

It is my understanding that with a neutral balance engine you could run a 6.75 inch or an 8 inch (or pretty much anything that is also neutral balance). I imagine your original is 6.75 by 2.375 and just over 8 lbs. But there are HD optional ones, 8 inch replacement ones, and so on.

**WIDESIDE72** · 01-14-2015, 11:41 PM

If you have the original short water pump you will need to run a 6.75" balancer. The 8" will interfere with the swp. If you have a swapped in lwp you can run either from a clearance standpoint, but im not sure about pulley alignment. I try to keep mine all either swp/6.75/ swp pulleys/ swp brackets or lwp/8"/lwp pulleys/ brackets.

01-14-2015, 09:47 AM	#1
1972 Jimmy Registered User Join Date: Nov 2012 Location: Freeland, Michigan Posts: 1,385	1972 350 Harmonic balancer help Hello all, Need some help determining what is the factory correct harmonic balancer for a 1972 350ci in my 4x4 jimmy. I'm not sure on the diameter or thickness. If anyone has the casting or part numbers the would be great as well! Thanks, Eric

01-14-2015, 08:07 PM	#2
1972 Jimmy Registered User Join Date: Nov 2012 Location: Freeland, Michigan Posts: 1,385	Re: 1972 350 Harmonic balancer help Anybody???

01-14-2015, 08:48 PM	#3
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: 1972 350 Harmonic balancer help Part numbers are all in the part number books. I will guess 12551537 but you'd have to look up your own truck. I found 10 on RockAuto.com, so not to be "that guy", but Google first. Long story short (more experience mechanics can correct me here if I'm wrong) the 350 is a neutral balance engine so as long as it fits your crank snout the only question you really need to answer is how much you want to spend. You can pick up a Dorman brand new for $30. You can spend $500 on a liquid-filled, SFI approved, turbocharged 3D version. It is my understanding that with a neutral balance engine you could run a 6.75 inch or an 8 inch (or pretty much anything that is also neutral balance). I imagine your original is 6.75 by 2.375 and just over 8 lbs. But there are HD optional ones, 8 inch replacement ones, and so on. __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

01-14-2015, 11:41 PM	#4
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,500	Re: 1972 350 Harmonic balancer help If you have the original short water pump you will need to run a 6.75" balancer. The 8" will interfere with the swp. If you have a swapped in lwp you can run either from a clearance standpoint, but im not sure about pulley alignment. I try to keep mine all either swp/6.75/ swp pulleys/ swp brackets or lwp/8"/lwp pulleys/ brackets.



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