Alright i'm hoping someone can shed light on this for me. Longstory short, I want to put LS3 pistons in my L92, is there any reason this can't be done while retaining VVT? Was this the purpose for the valve reliefs on L92 pistons?

 

I would imagine they are needed with stock cam specs.

 

That's why i'm not sure because the LS3 cam is bigger, so that shouldn't be an issue, I just don't know if the VVT function requires those valve reliefs.

 

VVT advances the cam a good bit at low speeds, which might be the reason why the reliefs are needed

 

Yes, that is why the pistons have valve reliefs. The VVT phaser has between 52 and 62 degrees of rotation, depending on the phaser, which will have a HUGE effect on PTV.

 

The L92 cam is pretty mild... I wouldn't be surprised if you could get away with flat-tops and not run into any PTV issues... I would still probably punch some numbers into a PTV calculator with the cam at full retard, straight up, and full advance... that should give you a pretty good idea of what you're working with. KCS has forgotten more than I will ever know, so definitely take anything I say with a grain of salt.

I like the L92 cam, actually, and would like to see what it can do in a 4.8/5.3 with some 1.85 rockers... assuming that somehow doesn't make a valve clip the block... but I highly doubt that would be the case with 198/209 .545/.545 115(?) cam, regardless of where it may be in its VVT phasing.