Harmonic balancer

**dezebe1** · 02-15-2014

The other day i was doing some digging online for a harmonic balancer for our LeMons race car due to the fact that we are going from N/A to Supercharged. Looked at aftermarket SFI balancers and figured we need to keep the engine looking stock so in my search I found a different part number between a GTP L67 and a Bonneville L67. Had our parts dept. pull the factory GM part nubers for each and found the Bonneville balancer is 3lbs. heavier. GTP 8.5lbs vs. SSEI 11.5
So figured I'd pass it along if anyone is looking for a beefier stock factory balancer that will help control harmonics better.

**Slick2500** · 02-15-2014

Thats kind of odd. And you got those part numbers lol?

**dezebe1** · 02-15-2014

Originally Posted by slick2500

Thats kind of odd. And you got those part numbers lol?

GM part #12563266 for the Bonneville balancer and 12563268 for the GTP balancer

**l67ss** · 02-16-2014

I wonder if its the same for a park avenue?

**sseilmnop** · 02-16-2014

Park Avenue and Bonneville have same motor mounts and pulleys, the balancer would be the same. Sure your comparing supercharged balancer from ssei with the gtp?

**Scottydoggs** · 02-16-2014

http://www.amazon.com/ACDelco-125632.../dp/B0049Z6VTG

http://www.amazon.com/ACDelco-125632.../dp/B0049Z4TMW

they looks the same to me, i wonder where the extra weight is? they dont list the weight on the ads.

**dezebe1** · 02-16-2014

Originally Posted by Scottydoggs

http://www.amazon.com/ACDelco-125632.../dp/B0049Z6VTG

http://www.amazon.com/ACDelco-125632.../dp/B0049Z4TMW

they looks the same to me, i wonder where the extra weight is? they dont list the weight on the ads.

The Bonneville is a thicker outer metal ring...same diameter overall just thicker. I had both up at the parts counter and put both on our shipping scale at the dealership. Feels much beefier also.
Disclaimer.....I'm not saying this aving the complete rotating assembly is the correct one for a GTP but for our race car we perfer to use it due to the fact we will be having the complete rotating assembly balanced with new JE pistons, ARP rod bolts so just wanted to share if anyone else is looking for another alternative

**dezebe1** · 02-16-2014

Originally Posted by sseilmnop

Park Avenue and Bonneville have same motor mounts and pulleys, the balancer would be the same. Sure your comparing supercharged balancer from ssei with the gtp?

if you don't belive it you can even look up the difference on rock auto. So yes I am 100% sure and I didn't mention anything about a Park Avenue. Look them up both as a 2003 model year

**Turbocharged400sbc** · 02-16-2014

its mostly for NVH reasons the luxury cars got the heavier damper, so yeah its better but only to the point that its optimal damping rpm is well below what we run. remember calculated life at wot was less than 5%, mostly the motor turns under 3k as its a low/mid range tq monster.

also with as many outer rings ive seen seperate...id stick with sfi