Pushrod lean angle on 91-up engines. The lifters are square to the lifter bore but they're not quite square to the rocker arm slot for the pushrod.
There is a slight lean angle between the lifters and the rocker arms as shown below.
The pushrod tubes line up square with the lifter blocks and hide the lean angle of the pushrods.
In the pics below, a inside bore gauge is lined up app. straight from the lifter bore to the rocker arm slot for the pushrod.
This is the app. lean angle of the pushrods between the lifter and the rocker arm.
The pushrod angle also changes as the rocker arm moves thru it's arc while the valve is opened and closed. ¹⁾

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