Repair your own idler / tensioner with our kit which includes a dust cover and is for use on all 289, 302, or 390 engines. After 40 years of heat and use, many idler adjusting bearings have seized or are on their way out. This is your answer! This part requires a press to install it. Bearing surface is 1-7/16", bearing diameter is 1.180". Fits these pulleys only: Some applications require that the shaft be cut down, measure twice, cut once.