[Jrainman]

Also I wanted to add while researching the same conversion as you are looking to do. I found my L31 crate engine timing cover had 2 less holes then the old style metal timing cover, so it would have required to drill and tap .. and also I just wanted to add that they do sell a vortec plastic timing cover with out the sensor hole P/N 12562818 this cover was used on the zz4 engine if I remember rite .