Just an FYI that there is a different block used on the C4500 and bigger trucks that is used on the C/K 2500 and 3500's. there is a extra casing on these blocks compared to the pick up truck block I will post photos later this week to show the difference. I found this after fully dressing a LB7 getting ready to install in my 4500 and the last thing to put on was the motor mounts and the casing was not there or the holes for the 2 other mounting bolts for the mount where also not there