06BlackC6

Hey guys I am having an slp underdrive pulley installed on my 06 ls2 this weekend, and I was wondering what the part numbers were for the 2 belts needed. I was wanting to purchase the Goodyear Gatorback belts. Thanks in advance for any info!

NukeC5

Its an old thread, but I found it while searching for this answer. I need to know what Gatorback belt is for the 25% underdrive. Hopefully someone knows this by now...

NukeC5

So far I have found these belt numbers.

Main serpentine: 4060775
A/C: 4040410

These are both Goodyear Gatorbacks and are what I found for the SLP 25% underdrive damper.

I am planning on going with a Trickflow 25% underdrive damper. Its much cheaper and I know the brand to be higher quality. Now my question is, in order for a damper to be 25% underdrive, would it have to be a certain size? As in, would the Trickflow 25% UD be the same size as the SLP one?

LS1LT1

Just be careful with those published A/C belt numbers, I've seen a few cases where the number/belt size listed ended up not being the correct fit.

frankgtb

what does slp recommend????

NukeC5

The numbers I put down were collected from this site on old threads. They where what were agreed on for the SLP UD pulley. I'm pretty certain they are correct. I am not sure if they are correct for all 25% UD pulleys though.

NukeC5

More research is making me even more skeptical.. I'm not planning on going with summit racing's brand but I will use them as an example.

They sell two styles of UD pulleys available for the LSX engines. Part numbers C2502 with an outside diameter of 6.140" and part number C2503 with an outside diameter of 6.750". Both recommend different sized belts which leads me to believe that 25% under drive can be achieved in various ways...

The Gatorback belt recommended for the SLP main drive is 77.5"
One of the summit ones recommends the 78" Gatorback part# 4060780. I feel like either of these would work on both units because there is only a half inch difference.
The other summit one recommends the 76" Gatorback part# 4060760.

I am confused by the differences here and why they are present.

NukeC5

Ok, scratch that^^^

I just found that the different outside diameters are specific to vehicles. The one that is very similar in belt size recommended for the SLP one is corvette specific. That is summit part number C2503.
The other one is for the F-body's. (I was unaware that they had different size balancers). But that explains the difference.

So I think its safe to say that the Gatorback belt size required for a 25% UD pulley on the C5 is 4060775. I say that because you want to go with the shortest belt that fits correctly to decrease the possibility of noise. That is the one that guys on here have fit on the SLP balancer, and I'm sure would fit the summit or Trick-flow ones.

NukeC5

The belts to go with for 25% UD (If you want Gatorbacks) are:

Main serpentine: 4060775
A/C: 4040410

SDPC

The C6 uses a shorter A/C belt than the C5, due to the absent idler pulley. We use a 395, not the 410

NukeC5

Oh wow, I did not even realize I was in the C6 section. I guess the search function pulls up all areas huh.