wrong rocker arms ...!!!!

Ok got a question here working on a 440 with hydraulic flat tappet cam stock hydraulic lifters stock rocker arms..so I had a header flange exhaust leak got that taken care of and now I can hear what sounds like a few lifters tapping on same side I fixed leak . Pulled valvery cover and used a magnet to pull all the lifters out and lifters look good and are pumped up like they should be so I believe lifters are good..leaves me wonder what's up with the tap. I start checking out the rockers arm orientation to make sure it's correct and it looks fine..I kept looking at the rockers and noticed two of them are shorter then the rest so I'm thinking someone used to small block rockers on this when they rebuilt it..the small block rockers are a lot shorter so the rocker does not ride on the tip of the valve like it should. I got two correct rockers for it and installed but can't start just yet waiting on a fitting for carb swap. Do you guys think that we is what was causing I'm thinkingredients definitely..that short rocherry could have caused more damage then a tick that's very hard on the guides if it being pushed wrong..Thanks guys