I have a vy v6 and i have noticed that in your description for these rockers that they suit vs-vx commodore but with the 1.9.1 rockers in the product description it says that it will fit vs-vy commodore whats the difference between the ecotec engines?

"I have a vy v6 and i have noticed that in your description for these rockers that they suit vs-vx commodore but with the 1.9.1 rockers in the product description it says that it will fit vs-vy commodore whats the difference between the ecotec engines?" While the engines between models are very similar, there are some slight differences. In this instance, the VY Ecotec/L67 cylinder heads are slightly different to the earlier engines due to the way that they've been cast. This has resulted in excessive casting flash around the push rod area in the cylinder heads, reducing clearance between the pushrod and cylinder had. As a result when you install 1.98:1 ratio rockers on a VY, the push rods rub up against the cylinder heads resulting in noisy engine operation. Noise aside, if continued to run in this state, would ultimately cause the pushrods to fail due to the would be continually rubbing up against the cylinder head. In stating the above though, it is possible to clean up the casting flash around the pushrod area to allow the installation of these 1.98:1 rockers on your VY. While this work can be done with the cylinder heads still on the car if you're careful, ideally you would want to undertake this work with the cylinder heads off the car to avoid the risk getting of getting metal into the engine/oil.