1.6 huh? Do they kiss the holes thru the heads? I bought my last set in a chevy flavor because a stock length was perfect for my eddy head prw steel rocker mp solid combo. I got the hardened pushrods 'for use with guide plates'. Of course Im not using steel guide plates with a shaft rocker setup and the pushrod to head contact was very minor but since I'm not taking the head off to clearance it I figured hardened steel against soft aluminum wouldn't be likely to heat up and fail.