It's been my experience that a pushrod that is either too long or too short will primarily effect the sweep over the valve stem tip. To ensure that you have the proper pushrod length, you mock the valve train up and look for the signature of the roller tip across the valve stem tip, typically distinguished by coloring the vlave stem tip w/ a sharpie or marker and notating the wear pattern left by the rocker after you spin it over dry a few times. Too long and you're on the outside edge of the valve, too short and your on the inside. Long term results are worn valve guides due to poor geometry.
I've not heard of valves banging against the slugs b/c of pushrod length. But I'm always learning
Reply to original post- I'm running FMS hardened pushrods w/ my 185's, the stock 6.27 length. No problems here. Block has never been decked, 1.6 FMS rockers
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