Ive got a 98 4X4 Zr2 and have recently bought a 4.3 motor to replace the motor that was in it. The motor i bought was out of a 2wd the only difference i have seen is that the motor does not contain oil cooler lines. in order to swap the oil cooler lines from the old motor i must remove the oil filter and use a star key to remove the lines from the motor. i do not have a star key and was wondering if anyone knew what size i should be looking for. thanks for the help.