I need to get a pushrod legnth checker for my new set-up. Most of the pushrod checkers come in one inch or less ranges. The stock 351 pushrods are very close to what I need. My plan is to measur the stock pushrods and order a checker that falls in that range. What is the proper way to measure the stock pushrods? From ball tip to ball tip? Or just the shaft of the pushrod not including the ball tips?