What is the correct oil drain plug for the 96 LT1? I am getting conflicting info. I know for sure 94 and 95 are 1/2" x 20 (and for many, many years before). Some sources say this is also correct for the 96. Others say it is M12 x 1.75. Perhaps it is both with a running change in the year. The parts maintenance stickey in this section only lists one part number for 94 - 96 which is probably 1/2" x 20.