I have a set of Sportsman II's on my 400 and I am bending pushrods I have bent at least two so far, and they are random. I looked online at world castings website and read the technical info for these heads. It says the pushrod slots will need to be lengthened to use 1.6 ratio rockers. On the tech sheet that came with my heads which are a couple years older there is no mention of this. Have any of you guys ran into this problem with an older set of Sportsman's? I have ruled out all other possibilities for bending pushrods so this may be the reason.

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I hate weird valvetrain problems. Best way to go for starters is to borrow a set of 1.5s and put them on, see if the problem persists. Then you start to narrow stuff down. Put the stock rockers back on if that's all you have laying around.

Did you ckeck pushrod length with a MrGasket or Moroso pushrod length checker tool (you can use the MrGasket tool without yanking the intake)? Too long a pushrod can cause problems like this and I recall you are using an altered base circle cam, which would require different length pushrods (longer). But sometimes they over-do it recommending pushrods that are much too long.

If you are concerned about the pushrod being bent against the pushrod hole or guideplate just coat the appropriate area of the pushrod with machinist's dye, drop 'em back in, run the engine for a few secondsa and you'll see the dye wiped clean from the area if there is any serious side loading or binding going on.

I have never heard of problems with Sportsman IIs and 1.6 rockers.