Recently bought an '89 SSP. It has minor mods; Edelbrock intake, GT40P heads, headers, etc. It had some pretty serious lifter/rocker noise. Pulled the valve covers and found most of the rockers are REALLY lose. I ordered new hydraulic lifters and I need to get the correct length push rods. I bought the measurement tool, but once I get the "zero lash" measurement should I add any length to preload the lifters since they are new? I have read/watched quite a few procedures, but none of them address my specific situation. The car ran good, but just trying to fix A LOT of upgrade sins that were committed by one of the previous owners. Thanks in advance.