I have here a new ED timing kit from gmpd, and a cloyes oversized crank sprocket from thunder, so I have 2 crank sprockets. Can anyone tell me why they are the same size? How do these two sprockets differ? I figured that the oversized would be wider in diameter but they are the same!?! Only difference is the teeth do not line up when when put on top of eachother, which makes me think i should use the one in the set. All this talk about worn teeth has me worried. Which one should i use???

 

Cloyes makes GM sets.GM spect for the LT-1 crank sprocket is undersize v a normal small block set.Cloyes makes the LT-1 set in a standard small block size for the LT-1,it is a few thousands larger and will tighten the chain v an LT-1 set.You can run either one,but I prefer the small pulley GM set with a stock water pump.

 

LR, thanks for your post. Why is the smaller one better for the stock pump? What are the advantages of the oversized sprocket. I really just want the most reliable setup. But is there any noticable, drivable difference? Anyone else have opinions? Since I got it I might as well use it right?

 

The chain slack gives a little relief to the cam front brg,which these engines have a problem with.If you run an electric pump it takes the pump load off of the front cam brg.
There should be no problems with the "stock" one,but the larger one might cause premature wear on the front cam brg,especially if you have aftermarket springs,that put more load on the cam brgs.The gear drive water pump puts a lot of extra load on the front brg that a standard SBC doesn't have.This is IMO as to what causes the front cam brg to wear so quick.
The "oversize" sprocket will give a very small improvement in cam timing,and thats all.