Pushrod damage or more...? 289 mild

[Three Peaks]

Sounds like most of the usual culprits were already mentioned above. So, a couple rare issues that may come up and things to check-
What type of rocker arm mounts do you have? Pedestal or stud? If you are running aluminum heads, it is possible that the studs are pulling out of the head slowly. Not a common issue, but I've heard it happens.

Check your rocker tips for wear. I have the Comp Pro magnums on my 393 mainly because I had heard instances like yours of the tips on some of the Mag tips having issues on a couple car forums. No way to tell how accurate these reports are, but your wear pattern on the rod end is suspect at the least.

Overly heavy springs for the purpose could also cause some of the rod problems you are having. Did you check if your springs are suitable for the purpose? Proper seat pressure, no spring bind when loaded, installed properly?

Last thing for now- as mentioned above it sounds vaguely like a cam losing lobes. Take a micrometer and set it up on your head on each valve rocker to read at the rod lobe and run the engine through a rotation. Record this for each lobe (16). Hopefully, you know what the lift is supposed to be so you can check your results against the Cam card. If not, at the least comparing each measurement to the others, a few will pop out as being out of a reasonable amount of variance.

That should keep you busy for a while. Once you've checked out all the ideas above and this one, at the very least you should have an idea where this is headed.

Bob

[Texasdoc]

Originally Posted by Three Peaks

Overly heavy springs for the purpose could also cause some of the rod problems you are having. Did you check if your springs are suitable for the purpose? Proper seat pressure, no spring bind when loaded, installed properly?

This.

Most (a lot anyway) aftermarket heads seems to have springs for rollers, not tappets. Roller springs are generally too heavy for flat tappets. If you have two springs per valve (inner and outer), take the inner spring out for the break in procedure.

Even if you did everything right, you can wipe a cam lobe with ease.

[DD (CA)]

With massaged porting and screw in studs. So, the aftermarket Al head idea doesn't fly...

FWIW, Comp and Crower both pretty firm on "break in procedure" after new lifters / old cam, but I've also been reading some pretty astute counter arguments from HAMB, Z28 and hotrods sites.

Also informed me it was worthless to undergo break in now that I've driven it for a bit....

I'm torn a bit. Babied the thing so far, but if the rocker arms get loose again...

[jhv48]

FWIW, my cam was from Crower. But that was a long time ago.