So my husband and I had to replace this sensor this weekend and I am soo thankful that I had found this thread..... finding the bolts to go into the harmonic balancer was a chore...we got the 4inch ones and they were actually too long.....so we would say maybe a 3 1/2 inch ones if you can find them...but I am soo glad that I had found this or our car would still be sitting in the garage thank you very much!!!!!!