Numbers stamped in 440 rocker arms

[Bobby Sixkiller]

I’m swapping cams in one of my 440s. Going from a Chevy grind(I bought it this way) to a bone stock magnum cam. The pushrods are aftermarket so I took a core apart to use factory length pushrods. I noticed the numbers stamped on the rockers are different. One set is I 97. One is I 54. Maybe it’s +97 and +54. All factory rockers are the same right? I know my core is motor home engine. I’m pretty sure the other one is because of the 5/8 spark plugs.

 

[turbine68rt]

Depending on which cam/lifters you go with be sure to check the lifter preload, even with a stock replacement set. I think it's usually around .020"-.040"
Also check for excess play with the rocker loose on the shaft. That can also effect the preload reading.

 

[beanhead]

I’m swapping cams in one of my 440s. Going from a Chevy grind(I bought it this way) to a bone stock magnum cam. The pushrods are aftermarket so I took a core apart to use factory length pushrods. I noticed the numbers stamped on the rockers are different. One set is I 97. One is I 54. Maybe it’s +97 and +54. All factory rockers are the same right? I know my core is motor home engine. I’m pretty sure the other one is because of the 5/8 spark plugs.

I don't know what the stamps actually mean, I have some with '84' on them. They come in pairs of left and right rockers so as long as you get them back in the correct orientation no worries. Spark plug type would have nothing to do with the rockers..