Probably since one is strictly for an LT1 while the double roller is for all SBC's.

This is the one I bought,

I think it was $90 from Jegs.

 

That right there explains it all.

That's a nice setup. How do the double roller setups compare to the LT$ extreme duty?

 

Seems to have quicker throttle response. My car isn't running yet, but we installed the Comp Cams one which is very similiar to the Cloyes one I have and it made a difference on my friends 82 T/A with a 96 LT1 motor, but then again we also put the electric pump on.
Same thing with a friends 95 Z28, he went from the ED setup to teh comp cams chain and Electric pump and felt a noticeable difference

 

What about the LT4 production timing chain set? Isn't it supposed to be stronger than the LT1?

 

I think the ED (extreme duty?) that's been referred to above, is the lt4 set. And yep, it's stronger than the lt1 chain, but pricey though. ED is a single roller, if I remember correctly

 

The oem LT4 timing set is not the same as the GMPP Extreme Duty timing set. Everyone keep using the term "LT4 ED" set, but it is not called the LT4 ED. It is called the Extreme Duty Timing Set for LT1/LT4 engines. I believe that creates some of the confusion.

 

Cool - I didnt know that.

What's the difference between the two?

 

The ED set is much stronger and costs about the same as the weaker LT4 set. I went through this education process when I was considering a new chain when I redid the cam.

In my opinion between the oem LT1, the LT4 and the ED set, it is a no-brainer. For the slight higher price, the ED is so much more beefier roller chain with hardened gears. When you see the LT1 chain next to the ED chain, one wonders why anyone would use another LT1 chain. The LT4 chain is not much better than the LT1 for the price.

 

Yup, that's what I meant. The LT4 OEM. At one time, maybe 2-3 years ago, people here were using it left and right. I guess it was a good alternative over the LT1 oem.

 

Just FYI, Cloyes DOES offer a direct replacement timing chain for the LT1s W/ the provision for the late model (vented Opti only) setup. I just got off the phone with Cloyes.