Originally Posted by
Yellow2k1vette
I have notched 862 5.3 heads, and have been running Cometic MLS gaskets for the past 12k miles with not a drop of coolant missing. The previous owner of these heads claims to have run them with GM MLS with no problems too.
I'm not 100% sure about the GM MLS (at least not from personal experience), but I do believe GM soon corrected the MLS design to accommodate the notch and be backwards-compatible many years ago after people discovered this to be a major problem.
It might still be preached on LS1tech today, but old stories are tough to kill sometimes. I do know for sure the Cometic MLS WILL work with notched heads.
:haveabeer