Engine Push Rods

what heads and rockers are on the car. The noise could be anything from improper adjusted rockers, to a collapsed lifter, to weak valve springs. To properly check the push rod length, you need an adjustable push rod length checker. The procedure to do this has been written up many times. You essentially want the rocker to come in contact with the center of the valve stem. Before you start pulling anything apart, figure out what the problem is.

Why do you need to put a FPR on. Is the old one not working? Pull the vacuum line off the end of the FPR. Do you smell or feel gas in the line? That would indicate the diaphragm is failing. For 99% of n/a cars, 39-41 is the right setting. You really don't need anything but the stock FPR, as your car will adjust it to around 39 automatically. The reason to get an adjustable FPR is if you want to tune the car or are adding a blower.